harmony 鸿蒙@ohos.data.distributedData (Distributed Data Management)

  • 2022-08-09
  • 浏览 (444)

@ohos.data.distributedData (Distributed Data Management)

The distributed data management module implements collaboration between databases of different devices for applications. The APIs provided by distributed data management can be used to save data to distributed databases and perform operations such as adding, deleting, modifying, querying, and synchronizing data in distributed databases.

This module provides the following functions:

  • KVManager: provides a KVManager instance to manage key-value (KV) stores.
  • KvStoreResultSet8+: provides methods to obtain the KV store result set and query or move the data read position.
  • Query8+: provides methods to query data from the database through a Query instance by using predicates.
  • KVStore: provides methods to add data, delete data, and observe data changes and data synchronization through a KVStore instance.
  • SingleKVStore: provides methods to query and synchronize data in a single KV store. This class inherits from KVStore, and data is not distinguished by device.
  • DeviceKVStore8+: provides methods to query and synchronize data in a device KV store. This class inherits from KVStore, and data is distinguished by device.

NOTE

  • The APIs provided by this module are no longer maintained since API version 9. You are advised to use @ohos.data.distributedKVStore.

  • The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.

  • All the APIs that need to obtain deviceId in this module are available only to system applications.

Modules to Import

import distributedData from '@ohos.data.distributedData';

distributedData.createKVManager

createKVManager(config: KVManagerConfig, callback: AsyncCallback<KVManager>): void

Creates a KVManager instance to manage KV stores. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
config KVManagerConfig Yes Configuration of the KVManager instance, including the bundle name and user information of the caller.
callback AsyncCallback<KVManager> Yes Callback invoked to return the KVManager instance created.

Example


let kvManager;
try {
    const kvManagerConfig = {
        bundleName : 'com.example.datamanagertest',
        userInfo : {
            userId : '0',
            userType : distributedData.UserType.SAME_USER_ID
        }
    }
    distributedData.createKVManager(kvManagerConfig, function (err, manager) {
        if (err) {
            console.log("Failed to create KVManager: "  + JSON.stringify(err));
            return;
        }
        console.log("Created KVManager successfully");
        kvManager = manager;
    });
} catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

distributedData.createKVManager

createKVManager(config: KVManagerConfig): Promise<KVManager>

Creates a KVManager instance to manage KV stores. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
config KVManagerConfig Yes Configuration of the KVManager instance, including the bundle name and user information of the caller.

Return value

Type Description
Promise<KVManager> Promise used to return the KVManager instance created.

Example


try {
  const kvManagerConfig = {
    bundleName: 'com.example.datamanagertest',
    userInfo: {
      userId: '0',
      userType: distributedData.UserType.SAME_USER_ID
    }
  }
  distributedData.createKVManager(kvManagerConfig).then((manager) => {
    console.log("Created KVManager successfully");
    kvManager = manager;
  }).catch((err) => {
    console.error("Failed to create KVManager: " + JSON.stringify(err));
  });
} catch (e) {
  console.log("An unexpected error occurred. Error:" + e);
}

KVManagerConfig

Provides configuration of the KVManager object, including the bundle name and user information of the caller.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Name Type Mandatory Description
userInfo UserInfo Yes User information.
bundleName string Yes Bundle name of the caller.

UserInfo

Defines user information.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Name Type Mandatory Description
userId string No User ID. The default value is 0.
userType UserType No User type. The default value is 0.

UserType

Enumerates the user types.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Name Value Description
SAME_USER_ID 0 User who logs in to different devices using the same account.

KVManager

Creates a KVManager object to obtain KV store information. Before calling any method in KVManager, you must use createKVManager to create a KVManager object.

getKVStore

getKVStore<T extends KVStore>(storeId: string, options: Options, callback: AsyncCallback<T>): void

Creates and obtains a KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
storeId string Yes Unique identifier of the KV store. The length cannot exceed MAX_STORE_ID_LENGTH.
options Options Yes Configuration of the KV store.
callback AsyncCallback<T> Yes Callback invoked to return the KV store instance created.

Example

let kvStore;
let kvManager;
try {
    const options = {
        createIfMissing : true,
        encrypt : false,
        backup : false,
        autoSync : true,
        kvStoreType : distributedData.KVStoreType.SINGLE_VERSION,
        securityLevel : distributedData.SecurityLevel.S2,
    };
    kvManager.getKVStore('storeId', options, function (err, store) {
        if (err) {
            console.log("getKVStore err: "  + JSON.stringify(err));
            return;
        }
        console.log("getKVStore success");
        kvStore = store;
    });
} catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

getKVStore

getKVStore<T extends KVStore>(storeId: string, options: Options): Promise<T>

Creates and obtains a KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
storeId string Yes Unique identifier of the KV store. The length cannot exceed MAX_STORE_ID_LENGTH.
options Options Yes Configuration of the KV store.

Return value

Type Description
Promise<T>, <T extends KVStore> Promise used to return the KV store instance created.

Example

let kvStore;
let kvManager;
try {
    const options = {
        createIfMissing : true,
        encrypt : false,
        backup : false,
        autoSync : true,
        kvStoreType : distributedData.KVStoreType.SINGLE_VERSION,
        securityLevel : distributedData.SecurityLevel.S2,
    };
    kvManager.getKVStore('storeId', options).then((store) => {
        console.log("getKVStore success");
        kvStore = store;
    }).catch((err) => {
        console.log("getKVStore err: "  + JSON.stringify(err));
    });
} catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

closeKVStore8+

closeKVStore(appId: string, storeId: string, kvStore: KVStore, callback: AsyncCallback<void>): void

Closes a KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
appId string Yes Bundle name of the app that invokes the KV store.
storeId string Yes Unique identifier of the KV store to close. The length cannot exceed MAX_STORE_ID_LENGTH.
kvStore KVStore Yes KV store to close.
callback AsyncCallback<void> Yes Callback invoked to return the result.

Example

let kvStore;
let kvManager;
const options = {
    createIfMissing: true,
    encrypt: false,
    backup: false,
    autoSync: true,
    kvStoreType: distributedData.KVStoreType.SINGLE_VERSION,
    schema: undefined,
    securityLevel: distributedData.SecurityLevel.S2,
}
try {
    kvManager.getKVStore('storeId', options, async function (err, store) {
        console.log('getKVStore success');
        kvStore = store;
        kvManager.closeKVStore('appId', 'storeId', kvStore, function (err, data) {
            console.log('closeKVStore success');
        });
    });
} catch (e) {
    console.log('closeKVStore e ' + e);
}

closeKVStore8+

closeKVStore(appId: string, storeId: string, kvStore: KVStore): Promise<void>

Closes a KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
appId string Yes Bundle name of the app that invokes the KV store.
storeId string Yes Unique identifier of the KV store to close. The length cannot exceed MAX_STORE_ID_LENGTH.
kvStore KVStore Yes KV store to close.

Return value

Type Description
Promise<void> Promise that returns no value.

Example

let kvManager;
let kvStore;
const options = {
    createIfMissing: true,
    encrypt: false,
    backup: false,
    autoSync: true,
    kvStoreType: distributedData.KVStoreType.SINGLE_VERSION,
    schema: undefined,
    securityLevel: distributedData.SecurityLevel.S2,
}
try {
    kvManager.getKVStore('storeId', options).then(async (store) => {
        console.log('getKVStore success');
        kvStore = store;
        kvManager.closeKVStore('appId', 'storeId', kvStore).then(() => {
            console.log('closeKVStore success');
        }).catch((err) => {
            console.log('closeKVStore err ' + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log('CloseKVStore getKVStore err ' + JSON.stringify(err));
    });
} catch (e) {
    console.log('closeKVStore e ' + e);
}

deleteKVStore8+

deleteKVStore(appId: string, storeId: string, callback: AsyncCallback&lt;void&gt;): void

Deletes a KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
appId string Yes Bundle name of the app that invokes the KV store.
storeId string Yes Unique identifier of the KV store to delete. The length cannot exceed MAX_STORE_ID_LENGTH.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvManager;
let kvStore;
const options = {
    createIfMissing : true,
    encrypt : false,
    backup : false,
    autoSync : true,
    kvStoreType : distributedData.KVStoreType.SINGLE_VERSION,
    schema : undefined,
    securityLevel : distributedData.SecurityLevel.S2,
}
try {
    kvManager.getKVStore('store', options, async function (err, store) {
        console.log('getKVStore success');
        kvStore = store;
        kvManager.deleteKVStore('appId', 'storeId', function (err, data) {
            console.log('deleteKVStore success');
        });
    });
} catch (e) {
    console.log('DeleteKVStore e ' + e);
}

deleteKVStore8+

deleteKVStore(appId: string, storeId: string): Promise&lt;void&gt;

Deletes a KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
appId string Yes Bundle name of the app that invokes the KV store.
storeId string Yes Unique identifier of the KV store to delete. The length cannot exceed MAX_STORE_ID_LENGTH.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvManager;
let kvStore;
const options = {
    createIfMissing : true,
    encrypt : false,
    backup : false,
    autoSync : true,
    kvStoreType : distributedData.KVStoreType.SINGLE_VERSION,
    schema : undefined,
    securityLevel : distributedData.SecurityLevel.S2,
}
try {
    kvManager.getKVStore('storeId', options).then(async (store) => {
        console.log('getKVStore success');
        kvStore = store;
        kvManager.deleteKVStore('appId', 'storeId').then(() => {
            console.log('deleteKVStore success');
        }).catch((err) => {
            console.log('deleteKVStore err ' + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log('getKVStore err ' + JSON.stringify(err));
    });
} catch (e) {
    console.log('deleteKVStore e ' + e);
}

getAllKVStoreId8+

getAllKVStoreId(appId: string, callback: AsyncCallback&lt;string[]&gt;): void

Obtains the IDs of all KV stores that are created by getKVStore() and have not been deleted by deleteKVStore(). This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
appId string Yes Bundle name of the app that invokes the KV store.
callback AsyncCallback&lt;string[]&gt; Yes Callback invoked to return the IDs of all created KV stores.

Example

let kvManager;
try {
    kvManager.getAllKVStoreId('appId', function (err, data) {
        console.log('GetAllKVStoreId success');
        console.log('GetAllKVStoreId size = ' + data.length);
    });
} catch (e) {
    console.log('GetAllKVStoreId e ' + e);
}

getAllKVStoreId8+

getAllKVStoreId(appId: string): Promise&lt;string[]&gt;

Obtains the IDs of all KV stores that are created by getKVStore() and have not been deleted by deleteKVStore(). This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
appId string Yes Bundle name of the app that invokes the KV store.

Return value

Type Description
Promise&lt;string[]&gt; Promise used to return the IDs of all created KV stores.

Example

let kvManager;
try {
    console.log('GetAllKVStoreId');
    kvManager.getAllKVStoreId('appId').then((data) => {
        console.log('getAllKVStoreId success');
        console.log('size = ' + data.length);
    }).catch((err) => {
        console.log('getAllKVStoreId err ' + JSON.stringify(err));
    });
} catch(e) {
    console.log('getAllKVStoreId e ' + e);
}

on(‘distributedDataServiceDie’)8+

on(event: ‘distributedDataServiceDie’, deathCallback: Callback&lt;void&gt;): void

Subscribes to service status changes.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
event string Yes Event to subscribe to. The value is distributedDataServiceDie, which indicates a service status change event.
deathCallback Callback&lt;void&gt; Yes Callback invoked to return a service status change event.

Example

let kvManager;
try {
    console.log('KVManagerOn');
    const deathCallback = function () {
        console.log('death callback call');
    }
    kvManager.on('distributedDataServiceDie', deathCallback);
} catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

off(‘distributedDataServiceDie’)8+

off(event: ‘distributedDataServiceDie’, deathCallback?: Callback&lt;void&gt;): void

Unsubscribes from service status changes.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
event string Yes Event to unsubscribe from. The value is distributedDataServiceDie, which indicates a service status change event.
deathCallback Callback&lt;void&gt; No Callback for the service status change event. If the callback is not specified, all subscriptions to the service status change event are canceled.

Example

let kvManager;
try {
    console.log('KVManagerOff');
    const deathCallback = function () {
        console.log('death callback call');
    }
    kvManager.off('distributedDataServiceDie', deathCallback);
} catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

Options

Provides KV store configuration.

Name Type Mandatory Description
createIfMissing boolean No Whether to create a KV store if the database file does not exist. The default value is true, which means to create a KV store.
System capability: SystemCapability.DistributedDataManager.KVStore.Core
encrypt boolean No Whether to encrypt the KV store. The default value is false, which means the KV store is not encrypted.
System capability: SystemCapability.DistributedDataManager.KVStore.Core
backup boolean No Whether to back up the KV store. The default value is true, which means to back up the KV store.
System capability: SystemCapability.DistributedDataManager.KVStore.Core
autoSync boolean No Whether to automatically synchronize database files. The default value is false, which means the database files are manually synchronized.
System capability: SystemCapability.DistributedDataManager.KVStore.Core
Required permissions: ohos.permission.DISTRIBUTED_DATASYNC
kvStoreType KVStoreType No Type of the KV store to create. The default value is DEVICE_COLLABORATION, which indicates a device KV store.
System capability: SystemCapability.DistributedDataManager.KVStore.Core
securityLevel SecurityLevel Yes Security level (S1 to S4) of the KV store.
System capability: SystemCapability.DistributedDataManager.KVStore.Core
schema8+ Schema No Schema used to define the values stored in the KV store. The default value is undefined, which means no schema is used.
System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

KVStoreType

Enumerates the KV store types.

Name Value Description
DEVICE_COLLABORATION 0 Device KV store.
The device KV store manages data by device, which eliminates conflicts. Data can be queried by device.
System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore
SINGLE_VERSION 1 Single KV store.
The single KV store does not differentiate data by device. If the same key is modified by different devices, the data will be overwritten.
System capability: SystemCapability.DistributedDataManager.KVStore.Core
MULTI_VERSION 2 Multi-version KV store. This type is not supported currently.
System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

SecurityLevel

Enumerates the KV store security levels.

Name Value Description
NO_LEVEL 0 No security level is set for the KV store (deprecated).
System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore
S0 1 The KV store security level is public (deprecated).
System capability: SystemCapability.DistributedDataManager.KVStore.Core
S1 2 The KV store security level is low. If data leakage occurs, minor impact will be caused. For example, a KV store that contains system data such as wallpapers.
System capability: SystemCapability.DistributedDataManager.KVStore.Core
S2 3 The KV store security level is medium. If data leakage occurs, moderate impact will be caused. For example, a KV store that contains information created by users or call records such as audio or video clips.
System capability: SystemCapability.DistributedDataManager.KVStore.Core
S3 5 The KV store security level is high. If data leakage occurs, major impact will be caused. For example, a KV store that contains information such as user fitness, health, and location data.
System capability: SystemCapability.DistributedDataManager.KVStore.Core
S4 6 The KV store security level is critical. If data leakage occurs, severe impact will be caused. For example, a KV store that contains information such as authentication credentials and financial data.
System capability: SystemCapability.DistributedDataManager.KVStore.Core

Constants

Defines the KV store constants.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Name Value Description
MAX_KEY_LENGTH 1024 Maximum length of a key in the KV store, in bytes.
MAX_VALUE_LENGTH 4194303 Maximum length of a value in the KV store, in bytes.
MAX_KEY_LENGTH_DEVICE 896 Maximum length of a device key, in bytes.
MAX_STORE_ID_LENGTH 128 Maximum length of a KV store ID, in bytes.
MAX_QUERY_LENGTH 512000 Maximum query length, in bytes.
MAX_BATCH_SIZE 128 Maximum number of batch operations.

Schema8+

Defines the schema of a KV store. You can create a Schema object and place it in Options when creating or opening a KV store.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Name Type Readable Writable Description
root8+ FieldNode Yes Yes JSON root object.
indexes8+ Array<string> Yes Yes String array in JSON format.
mode8+ number Yes Yes Schema mode.
skip8+ number Yes Yes Size of a skip of the schema.

constructor8+

constructor()

A constructor used to create a Schema instance.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

FieldNode8+

Represents a Schema instance, which provides the methods for defining the values stored in a KV store.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Name Type Readable Writable Description
nullable8+ boolean Yes Yes Whether the database field can be null.
default8+ string Yes Yes Default value of a FieldNode.
type8+ number Yes Yes Value of the data type corresponding to the specified node.

constructor8+

constructor(name: string)

A constructor used to create a FieldNode instance with a string field.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
name string Yes Value of FieldNode.

appendChild8+

appendChild(child: FieldNode): boolean

Appends a child node to this FieldNode.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
child FieldNode Yes Child node to append.

Return value

Type Description
boolean Returns true if the operation is successful; returns false otherwise.

Example

import ddm from '@ohos.data.distributedData';
try {
    let node = new ddm.FieldNode("root");
    let child1 = new ddm.FieldNode("child1");
    let child2 = new ddm.FieldNode("child2");
    let child3 = new ddm.FieldNode("child3");
    node.appendChild(child1);
    node.appendChild(child2);
    node.appendChild(child3);
    console.log("appendNode " + JSON.stringify(node));
    child1 = null;
    child2 = null;
    child3 = null;
    node = null;
} catch (e) {
    console.log("AppendChild " + e);
}

KvStoreResultSet8+

Provides methods to obtain the KV store result sets, and query and move the data read position.

Before calling any method in KvStoreResultSet, you must use getKVStore to obtain a KVStore object.

getCount8+

getCount(): number

Obtains the total number of rows in the result set.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
number Total number of rows obtained.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const count = resultSet.getCount();
    console.log("getCount succeed:" + count);
} catch (e) {
    console.log("getCount failed: " + e);
}

getPosition8+

getPosition(): number

Obtains the current data read position (position from which data is read) in the result set.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
number Current data read position obtained.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeeded.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const position = resultSet.getPosition();
    console.log("getPosition succeed:" + position);
} catch (e) {
    console.log("getPosition failed: " + e);
}

moveToFirst8+

moveToFirst(): boolean

Moves the data read position to the first row. If the result set is empty, false will be returned.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
boolean Returns true if the operation is successful; returns false otherwise.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const moved1 = resultSet.moveToFirst();
    console.log("moveToFirst succeed: " + moved1);
} catch (e) {
    console.log("moveToFirst failed " + e);
}

moveToLast8+

moveToLast(): boolean

Moves the data read position to the last row. If the result set is empty, false will be returned.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
boolean Returns true if the operation is successful; returns false otherwise.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const moved2 = resultSet.moveToLast();
    console.log("moveToLast succeed:" + moved2);
} catch (e) {
    console.log("moveToLast failed: " + e);
}

moveToNext8+

moveToNext(): boolean

Moves the data read position to the next row. If the result set is empty, false will be returned.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
boolean Returns true if the operation is successful; returns false otherwise.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const moved3 = resultSet.moveToNext();
    console.log("moveToNext succeed: " + moved3);
} catch (e) {
    console.log("moveToNext failed: " + e);
}

moveToPrevious8+

moveToPrevious(): boolean

Moves the data read position to the previous row. If the result set is empty, false will be returned.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
boolean Returns true if the operation is successful; returns false otherwise.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const moved4 = resultSet.moveToPrevious();
    console.log("moveToPrevious succeed:" + moved4);
} catch (e) {
    console.log("moveToPrevious failed: " + e);
}

move8+

move(offset: number): boolean

Moves the data read position with the specified offset from the current position.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
offset number Yes Offset to move the data read position. A negative value means to move backward, and a positive value means to move forward.

Return value

Type Description
boolean Returns true if the operation is successful; returns false otherwise.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const moved5 = resultSet.move(1);
    console.log("move succeed:" + moved5);
} catch (e) {
    console.log("move failed: " + e);
}

moveToPosition8+

moveToPosition(position: number): boolean

Moves the data read position from 0 to an absolute position.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
position number Yes Absolute position to move to.

Return value

Type Description
boolean Returns true if the operation is successful; returns false otherwise.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const moved6 = resultSet.moveToPosition(1);
    console.log("moveToPosition succeed: " + moved6);
} catch (e) {
    console.log("moveToPosition failed: " + e);
}

isFirst8+

isFirst(): boolean

Checks whether the data read position is the first row.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
boolean Returns true if the first row is being read; returns false otherwise.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const isfirst = resultSet.isFirst();
    console.log("Check isFirst succeed:" + isfirst);
} catch (e) {
    console.log("Check isFirst failed: " + e);
}

isLast8+

isLast(): boolean

Checks whether the data read position is the last row.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
boolean Returns true if the last row is being read; returns false otherwise.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const islast = resultSet.isLast();
    console.log("Check isLast succeed: " + islast);
} catch (e) {
    console.log("Check isLast failed: " + e);
}

isBeforeFirst8+

isBeforeFirst(): boolean

Checks whether the data read position is before the first row.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
boolean Returns true if the data read position is before the first row; returns false otherwise.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const isbeforefirst = resultSet.isBeforeFirst();
    console.log("Check isBeforeFirst succeed: " + isbeforefirst);
} catch (e) {
    console.log("Check isBeforeFirst failed: " + e);
}

isAfterLast8+

isAfterLast(): boolean

Checks whether the data read position is after the last row.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
boolean Returns true if the data read position is after the last row; returns false otherwise.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const isafterlast = resultSet.isAfterLast();
    console.log("Check isAfterLast succeed:" + isafterlast);
} catch (e) {
    console.log("Check isAfterLast failed: " + e);
}

getEntry8+

getEntry(): Entry

Obtains the KV pair from the current position.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
Entry KV pair obtained.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + err);
    });
    const entry  = resultSet.getEntry();
    console.log("getEntry succeed:" + JSON.stringify(entry));
} catch (e) {
    console.log("getEntry failed: " + e);
}

Query8+

Provides methods to create a Query object, which defines different data query criteria.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

constructor8+

constructor()

A constructor used to create a Schema instance.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

reset8+

reset(): Query

Resets the Query object.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
Query Query object reset.

Example

try {
    let query = new distributedData.Query();
    query.equalTo("key", "value");
    console.log("query is " + query.getSqlLike());
    query.reset();
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("simply calls should be ok :" + e);
}

equalTo8+

equalTo(field: string, value: number|string|boolean): Query

Creates a Query object to match the specified field whose value is equal to the given value.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
value number|string|boolean Yes Value specified.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.equalTo("field", "value");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

notEqualTo8+

notEqualTo(field: string, value: number|string|boolean): Query

Creates a Query object to match the specified field whose value is not equal to the specified value.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
value number|string|boolean Yes Value specified.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.notEqualTo("field", "value");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

greaterThan8+

greaterThan(field: string, value: number|string|boolean): Query

Creates a Query object to match the specified field whose value is greater than the specified value.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
value number|string|boolean Yes Value specified.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.greaterThan("field", "value");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

lessThan8+

lessThan(field: string, value: number|string): Query

Creates a Query object to match the specified field whose value is less than the specified value.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
value number|string Yes Value specified.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.lessThan("field", "value");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

greaterThanOrEqualTo8+

greaterThanOrEqualTo(field: string, value: number|string): Query

Creates a Query object to match the specified field whose value is greater than or equal to the specified value.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
value number|string Yes Value specified.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.greaterThanOrEqualTo("field", "value");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

lessThanOrEqualTo8+

lessThanOrEqualTo(field: string, value: number|string): Query

Creates a Query object to match the specified field whose value is less than or equal to the specified value.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
value number|string Yes Value specified.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.lessThanOrEqualTo("field", "value");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

isNull8+

isNull(field: string): Query

Creates a Query object to match the specified field whose value is null.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.isNull("field");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

inNumber8+

inNumber(field: string, valueList: number[]): Query

Creates a Query object to match the specified field whose value is within the specified list of numbers.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
valueList number[] Yes List of numbers.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.inNumber("field", [0, 1]);
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

inString8+

inString(field: string, valueList: string[]): Query

Creates a Query object to match the specified field whose value is within the specified list of strings.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
valueList string[] Yes List of strings.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.inString("field", ['test1', 'test2']);
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

notInNumber8+

notInNumber(field: string, valueList: number[]): Query

Creates a Query object to match the specified field whose value is not within the specified list of numbers.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
valueList number[] Yes List of numbers.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.notInNumber("field", [0, 1]);
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

notInString8+

notInString(field: string, valueList: string[]): Query

Creates a Query object to match the specified field whose value is not within the specified list of strings.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
valueList string[] Yes List of strings.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.notInString("field", ['test1', 'test2']);
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

like8+

like(field: string, value: string): Query

Creates a Query object to match the specified field whose value is similar to the specified string.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
value string Yes String specified.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.like("field", "value");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

unlike8+

unlike(field: string, value: string): Query

Creates a Query object to match the specified field whose value is not similar to the specified string.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.
value string Yes String specified.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.unlike("field", "value");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

and8+

and(): Query

Creates a Query object with the AND condition.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.notEqualTo("field", "value1");
    query.and();
    query.notEqualTo("field", "value2");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

or8+

or(): Query

Creates a Query object with the OR condition.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.notEqualTo("field", "value1");
    query.or();
    query.notEqualTo("field", "value2");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

orderByAsc8+

orderByAsc(field: string): Query

Creates a Query object to sort the query results in ascending order.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.notEqualTo("field", "value");
    query.orderByAsc("field");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

orderByDesc8+

orderByDesc(field: string): Query

Creates a Query object to sort the query results in descending order.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.notEqualTo("field", "value");
    query.orderByDesc("field");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

limit8+

limit(total: number, offset: number): Query

Creates a Query object to specify the number of results and where to start.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
total number Yes Number of results to query.
offset number Yes Start position for query.

Return value

Type Description
Query Query object created.

Example

let total = 10;
let offset = 1;
try {
    let query = new distributedData.Query();
    query.notEqualTo("field", "value");
    query.limit(total, offset);
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

isNotNull8+

isNotNull(field: string): Query

Creates a Query object to match the specified field whose value is not null.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
fieId string Yes Field to match. It cannot contain ‘^’.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.isNotNull("field");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

beginGroup8+

beginGroup(): Query

Creates a Query object for a query condition group with a left parenthesis.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.beginGroup();
    query.isNotNull("field");
    query.endGroup();
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

endGroup8+

endGroup(): Query

Creates a Query object for a query condition group with a right parenthesis.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.beginGroup();
    query.isNotNull("field");
    query.endGroup();
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

prefixKey8+

prefixKey(prefix: string): Query

Creates a Query object with a specified key prefix.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
prefix string Yes Key prefix.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.prefixKey("$.name");
    query.prefixKey("0");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
    console.log("duplicated calls should be ok :" + e);
}

setSuggestIndex8+

setSuggestIndex(index: string): Query

Creates a Query object with an index preferentially used for query.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
index string Yes Index preferentially used for query.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.setSuggestIndex("$.name");
    query.setSuggestIndex("0");
    console.log("query is " + query.getSqlLike());
    query = null;
} catch (e) {
   console.log("duplicated calls should be ok :" + e);
}

deviceId8+

deviceId(deviceId:string):Query

Creates a Query object with the device ID as the key prefix. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
deviceId string Yes Device ID.

Return value

Type Description
Query Query object created.

Example

try {
    let query = new distributedData.Query();
    query.deviceId("deviceId");
    console.log("query is " + query.getSqlLike());
} catch (e) {
    console.log("should be ok on Method Chaining : " + e);
}

getSqlLike8+

getSqlLike():string

Obtains the query statement of the Query object.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
string Returns the query statement obtained.

Example

try {
    let query = new distributedData.Query();
    let sql1 = query.getSqlLike();
    console.log("GetSqlLike sql=" + sql1);
} catch (e) {
    console.log("duplicated calls should be ok : " + e);
}

KVStore

Provides methods to manage data in a KV store, for example, adding or deleting data and subscribing to data changes or completion of data synchronization.

Before calling any method in KVStore, you must use getKVStore to obtain a KVStore object.

put

put(key: string, value: Uint8Array|string|number|boolean, callback: AsyncCallback&lt;void&gt;): void

Adds a KV pair of the specified type to this KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
key string Yes Key of the KV pair to add. It cannot be empty, and the length cannot exceed MAX_KEY_LENGTH.
value Uint8Array |string |number |boolean Yes Value of the KV pair to add. The value type can be Uint8Array, number, string, or boolean. A value of the Uint8Array or string type cannot exceed MAX_VALUE_LENGTH.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string';
const VALUE_TEST_STRING_ELEMENT = 'value-test-string';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT, function (err,data) {
        if (err != undefined) {
            console.log("put err: " + JSON.stringify(err));
            return;
        }
        console.log("put success");
    });
}catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

put

put(key: string, value: Uint8Array|string|number|boolean): Promise&lt;void&gt;

Adds a KV pair of the specified type to this KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
key string Yes Key of the KV pair to add. It cannot be empty, and the length cannot exceed MAX_KEY_LENGTH.
value Uint8Array |string |number |boolean Yes Value of the KV pair to add. The value type can be Uint8Array, number, string, or boolean. A value of the Uint8Array or string type cannot exceed MAX_VALUE_LENGTH.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string';
const VALUE_TEST_STRING_ELEMENT = 'value-test-string';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT).then((data) => {
        console.log("put success: " + JSON.stringify(data));
    }).catch((err) => {
        console.log("put err: " + JSON.stringify(err));
    });
}catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

delete

delete(key: string, callback: AsyncCallback&lt;void&gt;): void

Deletes a KV pair from this KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
key string Yes Key of the KV pair to delete. It cannot be empty, and the length cannot exceed MAX_KEY_LENGTH.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string';
const VALUE_TEST_STRING_ELEMENT = 'value-test-string';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT, function (err,data) {
        if (err != undefined) {
            console.log("put err: " + JSON.stringify(err));
            return;
        }
        console.log("put success");
        kvStore.delete(KEY_TEST_STRING_ELEMENT, function (err,data) {
            if (err != undefined) {
                console.log("delete err: " + JSON.stringify(err));
                return;
            }
            console.log("delete success");
        });
    });
}catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

delete

delete(key: string): Promise&lt;void&gt;

Deletes a KV pair from this KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
key string Yes Key of the KV pair to delete. It cannot be empty, and the length cannot exceed MAX_KEY_LENGTH.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string';
const VALUE_TEST_STRING_ELEMENT = 'value-test-string';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT).then((data) => {
        console.log("put success: " + JSON.stringify(data));
        kvStore.delete(KEY_TEST_STRING_ELEMENT).then((data) => {
            console.log("delete success");
        }).catch((err) => {
            console.log("delete err: " + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log("put err: " + JSON.stringify(err));
    });
}catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

on(‘dataChange’)

on(event: ‘dataChange’, type: SubscribeType, listener: Callback&lt;ChangeNotification&gt;): void

Subscribes to data changes of the specified type.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to subscribe to. The value is dataChange, which indicates a data change event.
type SubscribeType Yes Type of data change.
listener Callback&lt;ChangeNotification&gt; Yes Callback invoked to return a data change event.

Example

let kvStore;
kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_LOCAL, function (data) {
    console.log("dataChange callback call data: " + JSON.stringify(data));
});

on(‘syncComplete’)

on(event: ‘syncComplete’, syncCallback: Callback&lt;Array&lt;[string, number]&gt;&gt;): void

Subscribes to synchronization complete events.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to subscribe to. The value is syncComplete, which indicates a synchronization complete event.
syncCallback Callback&lt;Array&lt;[string, number]&gt;&gt; Yes Callback invoked to return a synchronization complete event.

Example

let kvStore;
kvStore.on('syncComplete', function (data) {
    console.log("callback call data: " + data);
});

off(‘dataChange’)8+

off(event:‘dataChange’, listener?: Callback&lt;ChangeNotification&gt;): void

Unsubscribes from data changes.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to unsubscribe from. The value is dataChange, which indicates a data change event.
listener Callback&lt;ChangeNotification&gt; No Callback for the data change event. If the callback is not specified, all subscriptions to the data change event are canceled.

Example

let kvStore;
class KvstoreModel {
    call(data) {
        console.log("dataChange: " + data);
    }
    subscribeDataChange() {
        if (kvStore != null) {
            kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_REMOTE, this.call);
        }
    }
    unsubscribeDataChange() {
        if (kvStore != null) {
            kvStore.off('dataChange', this.call);
        }
    }
}

off(‘syncComplete’)8+

off(event: ‘syncComplete’, syncCallback?: Callback&lt;Array&lt;[string, number]&gt;&gt;): void

Unsubscribes from synchronization complete events.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to unsubscribe from. The value is syncComplete, which indicates a synchronization complete event.
syncCallback Callback&lt;Array&lt;[string, number]&gt;&gt; No Callback for the synchronization complete event. If the callback is not specified, all subscriptions to the synchronization complete event are canceled.

Example

let kvStore;
class KvstoreModel {
    call(data) {
        console.log("syncComplete: " + data);
    }
    subscribeSyncComplete() {
        if (kvStore != null) {
            kvStore.on('syncComplete', this.call);
        }
    }
    unsubscribeSyncComplete() {
        if (kvStore != null) {
            kvStore.off('syncComplete', this.call);
        }
    }
}

putBatch8+

putBatch(entries: Entry[], callback: AsyncCallback&lt;void&gt;): void

Inserts KV pairs in batches to this KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
entries Entry[] Yes KV pairs to insert in batches.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + JSON.stringify(entries));
    kvStore.putBatch(entries, async function (err,data) {
        console.log('putBatch success');
        kvStore.getEntries('batch_test_string_key', function (err,entries) {
            console.log('getEntries success');
            console.log('entries.length: ' + entries.length);
            console.log('entries[0]: ' + JSON.stringify(entries[0]));
        });
    });
}catch(e) {
    console.log('PutBatch e ' + JSON.stringify(e));
}

putBatch8+

putBatch(entries: Entry[]): Promise&lt;void&gt;

Inserts KV pairs in batches to this KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
entries Entry[] Yes KV pairs to insert in batches.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + JSON.stringify(entries));
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
        kvStore.getEntries('batch_test_string_key').then((entries) => {
            console.log('getEntries success');
            console.log('PutBatch ' + JSON.stringify(entries));
        }).catch((err) => {
            console.log('getEntries fail ' + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log('putBatch fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('PutBatch e ' + JSON.stringify(e));
}

deleteBatch8+

deleteBatch(keys: string[], callback: AsyncCallback&lt;void&gt;): void

Deletes KV pairs in batches from this KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
keys string[] Yes KV pairs to delete in batches.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
try {
    let entries = [];
    let keys = [];
    for (var i = 0; i < 5; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
        keys.push(key + i);
    }
    console.log('entries: ' + JSON.stringify(entries));
    kvStore.putBatch(entries, async function (err,data) {
        console.log('putBatch success');
        kvStore.deleteBatch(keys, async function (err,data) {
            console.log('deleteBatch success');
        });
    });
}catch(e) {
    console.log('DeleteBatch e ' + e);
}

deleteBatch8+

deleteBatch(keys: string[]): Promise&lt;void&gt;

Deletes KV pairs in batches from this KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
keys string[] Yes KV pairs to delete in batches.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
try {
    let entries = [];
    let keys = [];
    for (var i = 0; i < 5; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
        keys.push(key + i);
    }
    console.log('entries: ' + JSON.stringify(entries));
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
        kvStore.deleteBatch(keys).then((err) => {
            console.log('deleteBatch success');
        }).catch((err) => {
            console.log('deleteBatch fail ' + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log('putBatch fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('DeleteBatch e ' + e);
}

startTransaction8+

startTransaction(callback: AsyncCallback&lt;void&gt;): void

Starts the transaction in this KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
function putBatchString(len, prefix) {
    let entries = [];
    for (var i = 0; i < len; i++) {
        var entry = {
            key : prefix + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    return entries;
}
try {
    var count = 0;
    kvStore.on('dataChange', 0, function (data) {
        console.log('startTransaction 0' + data)
        count++;
    });
    kvStore.startTransaction(async function (err,data) {
        console.log('startTransaction success');
        let entries = putBatchString(10, 'batch_test_string_key');
        console.log('entries: ' + JSON.stringify(entries));
        kvStore.putBatch(entries, async function (err,data) {
            console.log('putBatch success');
        });
    });
}catch(e) {
    console.log('startTransaction e ' + e);
}

startTransaction8+

startTransaction(): Promise&lt;void&gt;

Starts the transaction in this KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
try {
    var count = 0;
    kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_ALL, function (data) {
        console.log('startTransaction ' + JSON.stringify(data));
        count++;
    });
    kvStore.startTransaction().then(async (err) => {
        console.log('startTransaction success');
    }).catch((err) => {
        console.log('startTransaction fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('startTransaction e ' + e);
}

commit8+

commit(callback: AsyncCallback&lt;void&gt;): void

Commits the transaction in this KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
try {
    kvStore.commit(function (err,data) {
        if (err == undefined) {
            console.log('commit success');
        } else {
            console.log('commit fail');
        }
    });
}catch(e) {
    console.log('Commit e ' + e);
}

commit8+

commit(): Promise&lt;void&gt;

Commits the transaction in this KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
try {
    kvStore.commit().then(async (err) => {
        console.log('commit success');
    }).catch((err) => {
        console.log('commit fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('Commit e ' + e);
}

rollback8+

rollback(callback: AsyncCallback&lt;void&gt;): void

Rolls back the transaction in this KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
try {
    kvStore.rollback(function (err,data) {
        if (err == undefined) {
            console.log('commit success');
        } else {
            console.log('commit fail');
        }
    });
}catch(e) {
    console.log('Rollback e ' + e);
}

rollback8+

rollback(): Promise&lt;void&gt;

Rolls back the transaction in this KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
try {
    kvStore.rollback().then(async (err) => {
        console.log('rollback success');
    }).catch((err) => {
        console.log('rollback fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('Rollback e ' + e);
}

enableSync8+

enableSync(enabled: boolean, callback: AsyncCallback&lt;void&gt;): void

Sets data synchronization, which can be enabled or disabled. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
enabled boolean Yes Whether to enable data synchronization. The value true means to enable data synchronization, and false means the opposite.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
try {
    kvStore.enableSync(true, function (err,data) {
        if (err == undefined) {
            console.log('enableSync success');
        } else {
            console.log('enableSync fail');
        }
    });
}catch(e) {
    console.log('EnableSync e ' + e);
}

enableSync8+

enableSync(enabled: boolean): Promise&lt;void&gt;

Sets data synchronization, which can be enabled or disabled. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
enabled boolean Yes Whether to enable data synchronization. The value true means to enable data synchronization, and false means the opposite.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
try {
    kvStore.enableSync(true).then((err) => {
        console.log('enableSync success');
    }).catch((err) => {
        console.log('enableSync fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('EnableSync e ' + e);
}

setSyncRange8+

setSyncRange(localLabels: string[], remoteSupportLabels: string[], callback: AsyncCallback&lt;void&gt;): void

Sets the data synchronization range. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
localLabels string[] Yes Synchronization labels set for the local device.
remoteSupportLabels string[] Yes Synchronization labels set for remote devices.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
try {
    const localLabels = ['A', 'B'];
    const remoteSupportLabels = ['C', 'D'];
    kvStore.setSyncRange(localLabels, remoteSupportLabels, function (err,data) {
        console.log('SetSyncRange put success');
    });
}catch(e) {
    console.log('SetSyncRange e ' + e);
}

setSyncRange8+

setSyncRange(localLabels: string[], remoteSupportLabels: string[]): Promise&lt;void&gt;

Sets the data synchronization range. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
localLabels string[] Yes Synchronization labels set for the local device.
remoteSupportLabels string[] Yes Synchronization labels set for remote devices.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
try {
    const localLabels = ['A', 'B'];
    const remoteSupportLabels = ['C', 'D'];
    kvStore.setSyncRange(localLabels, remoteSupportLabels).then((err) => {
        console.log('setSyncRange success');
    }).catch((err) => {
        console.log('delete fail ' + err);
    });
}catch(e) {
    console.log('SetSyncRange e ' + e);
}

SubscribeType

Enumerates the subscription types.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Name Value Description
SUBSCRIBE_TYPE_LOCAL 0 Local data changes.
SUBSCRIBE_TYPE_REMOTE 1 Remote data changes.
SUBSCRIBE_TYPE_ALL 2 Local and remote data changes.

ChangeNotification

Defines the content of data change notifications, including inserted data, updated data, deleted data, and device ID.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Name Type Mandatory Description
insertEntries Entry[] Yes Data inserted.
updateEntries Entry[] Yes Data updated.
deleteEntries Entry[] Yes Data deleted.
deviceId string Yes UUID of the device.

Entry

Defines the KV pairs stored in the KV store.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Name Type Mandatory Description
key string Yes Key of the KV pair stored in the KV store.
value Value Yes Value of the KV pair stored in the KV store.

Value

Defines the value object in a KV store.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Name Type Mandatory Description
type ValueType Yes Type of the value.
value Uint8Array |string |number |boolean Yes Value of the KV pair stored in the KV store.

ValueType

Enumerates the data types.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Name Value Description
STRING 0 String.
INTEGER 1 Integer.
FLOAT 2 Float (single-precision floating point).
BYTE_ARRAY 3 Byte array.
BOOLEAN 4 Boolean.
DOUBLE 5 Double (double-precision floating point).

SingleKVStore

Provides methods to query and synchronize data in a single KV store. This class inherits from KVStore.

Data is not distinguished by device in a single KV store. The data written to different devices using the same key will be overwritten. For example, a single KV store can be used to synchronize a user’s calendar and contact data between different devices.

Before calling any method in SingleKVStore, you must use getKVStore to obtain a SingleKVStore instance.

get

get(key: string, callback: AsyncCallback&lt;Uint8Array|string|boolean|number&gt;): void

Obtains the value of the specified key. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
key string Yes Key of the value to obtain. It cannot be empty, and the length cannot exceed MAX_KEY_LENGTH.
callback AsyncCallback&lt;Uint8Array |string |boolean |number&gt; Yes Callback invoked to return the value obtained.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string';
const VALUE_TEST_STRING_ELEMENT = 'value-test-string';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT, function (err,data) {
        if (err != undefined) {
            console.log("put err: " + JSON.stringify(err));
            return;
        }
        console.log("put success");
        kvStore.get(KEY_TEST_STRING_ELEMENT, function (err,data) {
            console.log("get success data: " + data);
        });
    });
}catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

get

get(key: string): Promise&lt;Uint8Array|string|boolean|number&gt;

Obtains the value of the specified key. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
key string Yes Key of the value to obtain. It cannot be empty, and the length cannot exceed MAX_KEY_LENGTH.

Return value

Type Description
Promise&lt;Uint8Array |string |boolean |number&gt; Promise used to return the value obtained.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string';
const VALUE_TEST_STRING_ELEMENT = 'value-test-string';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT).then((data) => {
        console.log("put success: " + JSON.stringify(data));
        kvStore.get(KEY_TEST_STRING_ELEMENT).then((data) => {
            console.log("get success data: " + data);
        }).catch((err) => {
            console.log("get err: " + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log("put err: " + JSON.stringify(err));
    });
}catch (e) {
    console.log("An unexpected error occurred. Error:" + e);
}

getEntries8+

getEntries(keyPrefix: string, callback: AsyncCallback&lt;Entry[]&gt;): void

Obtains all KV pairs that match the specified key prefix. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
keyPrefix string Yes Key prefix to match.
callback AsyncCallback&lt;Entry[]&gt; Yes Callback invoked to return the KV pairs that match the specified prefix.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_number_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.INTEGER,
                value : 222
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries, async function (err,data) {
        console.log('putBatch success');
        kvStore.getEntries('batch_test_number_key', function (err,entries) {
            console.log('getEntries success');
            console.log('entries.length: ' + entries.length);
            console.log('entries[0]: ' + JSON.stringify(entries[0]));
        });
    });
}catch(e) {
    console.log('PutBatch e ' + e);
}

getEntries8+

getEntries(keyPrefix: string): Promise&lt;Entry[]&gt;

Obtains all KV pairs that match the specified key prefix. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
keyPrefix string Yes Key prefix to match.

Return value

Type Description
Promise&lt;Entry[]&gt; Promise used to return the KV pairs that match the specified prefix.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + entries);
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
        kvStore.getEntries('batch_test_string_key').then((entries) => {
            console.log('getEntries success');
            console.log('entries.length: ' + entries.length);
            console.log('entries[0]: ' + JSON.stringify(entries[0]));
            console.log('entries[0].value: ' + JSON.stringify(entries[0].value));
            console.log('entries[0].value.value: ' + entries[0].value.value);
        }).catch((err) => {
            console.log('getEntries fail ' + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log('putBatch fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('PutBatch e ' + e);
}

getEntries8+

getEntries(query: Query, callback: AsyncCallback&lt;Entry[]&gt;): void

Obtains the KV pairs that match the specified Query object. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
query Query Yes Key prefix to match.
callback AsyncCallback&lt;Entry[]&gt; Yes Callback invoked to return the KV pairs that match the specified Query object.

Example

let kvStore;
try {
    var arr = new Uint8Array([21,31]);
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_bool_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.BYTE_ARRAY,
                value : arr
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + JSON.stringify(entries));
    kvStore.putBatch(entries, async function (err,data) {
        console.log('putBatch success');
        const query = new distributedData.Query();
        query.prefixKey("batch_test");
        kvStore.getEntries(query, function (err,entries) {
            console.log('getEntries success');
            console.log('entries.length: ' + entries.length);
            console.log('entries[0]: ' + JSON.stringify(entries[0]));
        });
    });
    console.log('GetEntries success');
}catch(e) {
    console.log('GetEntries e ' + e);
}

getEntries8+

getEntries(query: Query): Promise&lt;Entry[]&gt;

Obtains the KV pairs that match the specified Query object. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.

Return value

Type Description
Promise&lt;Entry[]&gt; Promise used to return the KV pairs that match the specified Query object.

Example

let kvStore;
try {
    var arr = new Uint8Array([21,31]);
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_bool_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.BYTE_ARRAY,
                value : arr
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + JSON.stringify(entries));
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
        const query = new distributedData.Query();
        query.prefixKey("batch_test");
        kvStore.getEntries(query).then((entries) => {
            console.log('getEntries success');
        }).catch((err) => {
            console.log('getEntries fail ' + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log('GetEntries putBatch fail ' + JSON.stringify(err))
    });
    console.log('GetEntries success');
}catch(e) {
    console.log('GetEntries e ' + e);
}

getResultSet8+

getResultSet(keyPrefix: string, callback: AsyncCallback&lt;KvStoreResultSet&gt;): void

Obtains the result set with the specified prefix. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
keyPrefix string Yes Key prefix to match.
callback AsyncCallback&lt;KvStoreResultSet&gt; Yes Callback invoked to return the result set with the specified prefix.

Example

let kvStore;
try {
    let resultSet;
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries, async function (err, data) {
        console.log('GetResultSet putBatch success');
        kvStore.getResultSet('batch_test_string_key', async function (err, result) {
            console.log('GetResultSet getResultSet succeed.');
            resultSet = result;
            kvStore.closeResultSet(resultSet, function (err, data) {
                console.log('GetResultSet closeResultSet success');
            })
        });
    });
}catch(e) {
    console.log('GetResultSet e ' + e);
}

getResultSet8+

getResultSet(keyPrefix: string): Promise&lt;KvStoreResultSet&gt;

Obtains the result set with the specified prefix. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
keyPrefix string Yes Key prefix to match.

Return value

Type Description
Promise&lt;KvStoreResultSet&gt; Promise used to return the result set with the specified prefix.

Example

let kvStore;
try {
    let resultSet;
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
    }).catch((err) => {
        console.log('PutBatch putBatch fail ' + JSON.stringify(err));
    });
    kvStore.getResultSet('batch_test_string_key').then((result) => {
        console.log('GetResult getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + JSON.stringify(err));
    });
    kvStore.closeResultSet(resultSet).then((err) => {
        console.log('GetResult closeResultSet success');
    }).catch((err) => {
        console.log('closeResultSet fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('GetResult e ' + e);
}

getResultSet8+

getResultSet(query: Query, callback: AsyncCallback&lt;KvStoreResultSet&gt;): void

Obtains a KvStoreResultSet object that matches the specified Query object. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.
callback AsyncCallback&lt;KvStoreResultSet&gt; Yes Callback invoked to return the KvStoreResultSet object obtained.

Example

let kvStore;
try {
    let resultSet;
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries, async function (err, data) {
        console.log('putBatch success');
        const query = new distributedData.Query();
        query.prefixKey("batch_test");
        kvStore.getResultSet(query, async function (err, result) {
            console.log('getResultSet succeed.');
            resultSet = result;
        });
    });
} catch(e) {
    console.log('GetResultSet e ' + e);
}

getResultSet8+

getResultSet(query: Query): Promise&lt;KvStoreResultSet&gt;

Obtains a KvStoreResultSet object that matches the specified Query object. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.

Return value

Type Description
Promise&lt;KvStoreResultSet&gt; Promise used to return the KvStoreResultSet object obtained.

Example

let kvStore;
try {
    let resultSet;
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
    }).catch((err) => {
        console.log('putBatch fail ' + JSON.stringify(err));
    });
    const query = new distributedData.Query();
    query.prefixKey("batch_test");
    kvStore.getResultSet(query).then((result) => {
        console.log(' getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('GetResultSet e ' + e);
}

closeResultSet8+

closeResultSet(resultSet: KvStoreResultSet, callback: AsyncCallback&lt;void&gt;): void

Closes the KvStoreResultSet object obtained by SingleKvStore.getResultSet. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
resultSet KvStoreResultSet Yes KvStoreResultSet object to close.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
try {
    let resultSet = null;
    kvStore.closeResultSet(resultSet, function (err, data) {
        if (err == undefined) {
            console.log('closeResultSet success');
        } else {
            console.log('closeResultSet fail');
        }
    });
}catch(e) {
    console.log('CloseResultSet e ' + e);
}

closeResultSet8+

closeResultSet(resultSet: KvStoreResultSet): Promise&lt;void&gt;

Closes the KvStoreResultSet object obtained by SingleKvStore.getResultSet. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
resultSet KvStoreResultSet Yes KvStoreResultSet object to close.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
try {
    let resultSet = null;
    kvStore.closeResultSet(resultSet).then(() => {
        console.log('closeResultSet success');
    }).catch((err) => {
        console.log('closeResultSet fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('CloseResultSet e ' + e);
}

getResultSize8+

getResultSize(query: Query, callback: AsyncCallback&lt;number&gt;): void

Obtains the number of results that matches the specified Query object. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.
callback AsyncCallback&lt;number&gt; Yes Callback invoked to return the number of results that match the specified Query object.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries, async function (err, data) {
        console.log('putBatch success');
        const query = new distributedData.Query();
        query.prefixKey("batch_test");
        kvStore.getResultSize(query, async function (err, resultSize) {
            console.log('getResultSet succeed.');
        });
    });
} catch(e) {
    console.log('GetResultSize e ' + e);
}

getResultSize8+

getResultSize(query: Query): Promise&lt;number&gt;

Obtains the number of results that matches the specified Query object. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.

Return value

Type Description
Promise&lt;number&gt; Promise used to return the number of results obtained.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
    }).catch((err) => {
        console.log('putBatch fail ' + JSON.stringify(err));
    });
    const query = new distributedData.Query();
    query.prefixKey("batch_test");
    kvStore.getResultSize(query).then((resultSize) => {
        console.log('getResultSet succeed.');
    }).catch((err) => {
        console.log('getResultSet failed: ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('GetResultSize e ' + e);
}

removeDeviceData8+

removeDeviceData(deviceId: string, callback: AsyncCallback&lt;void&gt;): void

Deletes data of a device. This API uses an asynchronous callback to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string_2';
const VALUE_TEST_STRING_ELEMENT = 'value-string-002';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT, async function (err,data) {
        console.log('put success');
        const deviceid = 'no_exist_device_id';
        kvStore.removeDeviceData(deviceid, async function (err,data) {
            if (err == undefined) {
                console.log('removeDeviceData success');
            } else {
                console.log('removeDeviceData fail');
                kvStore.get(KEY_TEST_STRING_ELEMENT, async function (err,data) {
                    console.log('RemoveDeviceData get success');
                });
            }
        });
    });
}catch(e) {
    console.log('RemoveDeviceData e ' + e);
}

removeDeviceData8+

removeDeviceData(deviceId: string): Promise&lt;void&gt;

Deletes data of a device. This API uses a promise to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string_2';
const VALUE_TEST_STRING_ELEMENT = 'value-string-001';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT).then((err) => {
        console.log('removeDeviceData put success');
    }).catch((err) => {
        console.log('put fail ' + JSON.stringify(err));
    });
    const deviceid = 'no_exist_device_id';
    kvStore.removeDeviceData(deviceid).then((err) => {
        console.log('removeDeviceData success');
    }).catch((err) => {
        console.log('removeDeviceData fail ' + JSON.stringify(err));
    });
    kvStore.get(KEY_TEST_STRING_ELEMENT).then((data) => {
        console.log('get success data:' + data);
    }).catch((err) => {
        console.log('RemoveDeviceData get fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('RemoveDeviceData e ' + e);
}

sync

sync(deviceIds: string[], mode: SyncMode, delayMs?: number): void

Synchronizes the KV store manually. > NOTE > > deviceIds is the networkId in DeviceInfo, which is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
deviceIds string[] Yes List of networkIds of the devices in the same networking environment to be synchronized.
mode SyncMode Yes Synchronization mode.
delayMs number No Delay time allowed, in milliseconds. The default value is 0.

Example

import deviceManager from '@ohos.distributedHardware.deviceManager';

let devManager;
let kvStore;
const KEY_TEST_SYNC_ELEMENT = 'key_test_sync';
const VALUE_TEST_SYNC_ELEMENT = 'value-string-001';
// create deviceManager
deviceManager.createDeviceManager('bundleName', (err, value) => {
  if (!err) {
    devManager = value;
    let deviceIds = [];
    if (devManager != null) {
      var devices = devManager.getTrustedDeviceListSync();
      for (var i = 0; i < devices.length; i++) {
        deviceIds[i] = devices[i].networkId;
      }
    }
    try {
      kvStore.on('syncComplete', function (data) {
        console.log('Sync dataChange');
      });
      kvStore.put(KEY_TEST_SYNC_ELEMENT + 'testSync101', VALUE_TEST_SYNC_ELEMENT, function (err, data) {
        if (err != undefined) {
          console.log("put err: " + JSON.stringify(err));
          return;
        }
        console.log('Succeeded in putting data');
        const mode = distributedData.SyncMode.PULL_ONLY;
        kvStore.sync(deviceIds, mode, 1000);
      });
    } catch (e) {
      console.log('Sync e' + e);
    }
  }
});

on(‘dataChange’)8+

on(event: ‘dataChange’, type: SubscribeType, listener: Callback&lt;ChangeNotification&gt;): void

Subscribes to data changes of the specified type.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to subscribe to. The value is dataChange, which indicates a data change event.
type SubscribeType Yes Type of data change.
listener Callback&lt;ChangeNotification&gt; Yes Callback invoked to return a data change event.

Example

let kvStore;
kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_LOCAL, function (data) {
    console.log("dataChange callback call data: " + JSON.stringify(data));
});

on(‘syncComplete’)8+

on(event: ‘syncComplete’, syncCallback: Callback&lt;Array&lt;[string, number]&gt;&gt;): void

Subscribes to synchronization complete events.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to subscribe to. The value is syncComplete, which indicates a synchronization complete event.
syncCallback Callback&lt;Array&lt;[string, number]&gt;&gt; Yes Callback invoked to return a synchronization complete event.

Example

let kvStore;
const KEY_TEST_FLOAT_ELEMENT = 'key_test_float';
const VALUE_TEST_FLOAT_ELEMENT = 321.12;
try {
    kvStore.on('syncComplete', function (data) {
        console.log('syncComplete ' + data)
    });
    kvStore.put(KEY_TEST_FLOAT_ELEMENT, VALUE_TEST_FLOAT_ELEMENT).then((data) => {
        console.log('syncComplete put success');
    }).catch((error) => {
        console.log('syncComplete put fail ' + error);
    });
}catch(e) {
    console.log('syncComplete put e ' + e);
}

off(‘dataChange’)8+

off(event:‘dataChange’, listener?: Callback&lt;ChangeNotification&gt;): void

Unsubscribes from data changes.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to unsubscribe from. The value is dataChange, which indicates a data change event.
listener Callback&lt;ChangeNotification&gt; No Callback for the data change event. If the callback is not specified, all subscriptions to the data change event are canceled.

Example

let kvStore;
class KvstoreModel {
    call(data) {
        console.log("dataChange: " + data);
    }
    subscribeDataChange() {
        if (kvStore != null) {
            kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_REMOTE, this.call);
        }
    }
    unsubscribeDataChange() {
        if (kvStore != null) {
            kvStore.off('dataChange', this.call);
        }
    }
}

off(‘syncComplete’)8+

off(event: ‘syncComplete’, syncCallback?: Callback&lt;Array&lt;[string, number]&gt;&gt;): void

Unsubscribes from synchronization complete events.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to unsubscribe from. The value is syncComplete, which indicates a synchronization complete event.
syncCallback Callback&lt;Array&lt;[string, number]&gt;&gt; No Callback for the synchronization complete event. If the callback is not specified, all subscriptions to the synchronization complete event are canceled.

Example

let kvStore;
class KvstoreModel {
    call(data) {
        console.log("syncComplete: " + data);
    }
    subscribeSyncComplete() {
        if (kvStore != null) {
            kvStore.on('syncComplete', this.call);
        }
    }
    unsubscribeSyncComplete() {
        if (kvStore != null) {
            kvStore.off('syncComplete', this.call);
        }
    }
}

setSyncParam8+

setSyncParam(defaultAllowedDelayMs: number, callback: AsyncCallback&lt;void&gt;): void

Sets the default delay allowed for KV store synchronization. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
defaultAllowedDelayMs number Yes Default delay allowed for database synchronization, in ms.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
try {
    const defaultAllowedDelayMs = 500;
    kvStore.setSyncParam(defaultAllowedDelayMs, function (err,data) {
        console.log('SetSyncParam put success');
    });
}catch(e) {
    console.log('testSingleKvStoreSetSyncParam e ' + e);
}

setSyncParam8+

setSyncParam(defaultAllowedDelayMs: number): Promise&lt;void&gt;

Sets the default delay allowed for KV store synchronization. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
defaultAllowedDelayMs number Yes Default delay allowed for database synchronization, in ms.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
try {
    const defaultAllowedDelayMs = 500;
    kvStore.setSyncParam(defaultAllowedDelayMs).then((err) => {
        console.log('SetSyncParam put success');
    }).catch((err) => {
        console.log('SetSyncParam put fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('SetSyncParam e ' + e);
}

getSecurityLevel8+

getSecurityLevel(callback: AsyncCallback&lt;SecurityLevel&gt;): void

Obtains the security level of this KV store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
callback AsyncCallback&lt;SecurityLevel&gt; Yes Callback invoked to return the security level of the KV store.

Example

let kvStore;
try {
    kvStore.getSecurityLevel(function (err,data) {
        console.log('getSecurityLevel success');
    });
}catch(e) {
    console.log('GetSecurityLevel e ' + e);
}

getSecurityLevel8+

getSecurityLevel(): Promise&lt;SecurityLevel&gt;

Obtains the security level of this KV store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Return value

Type Description
Promise&lt;SecurityLevel&gt; Promise used to return the security level of the KV store.

Example

let kvStore;
try {
    kvStore.getSecurityLevel().then((data) => {
        console.log(' getSecurityLevel success');
    }).catch((err) => {
        console.log('getSecurityLevel fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('GetSecurityLevel e ' + e);
}

DeviceKVStore8+

Provides methods to query and synchronize data in a device KV store. This class inherits from KVStore.

Data is distinguished by device in a device KV store. Each device can only write and modify its own data. Data of other devices is read-only and cannot be modified.

For example, a device KV store can be used to implement image sharing between devices. The images of other devices can be viewed, but not be modified or deleted.

Before calling any method in DeviceKVStore, you must use getKVStore to obtain a DeviceKVStore object.

get8+

get(deviceId: string, key: string, callback: AsyncCallback&lt;boolean|string|number|Uint8Array&gt;): void

Obtains a string value that matches the specified device ID and key. This API uses an asynchronous callback to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
key string Yes Key to match.
callback AsyncCallback&lt;boolean|string|number|Uint8Array&gt; Yes Callback invoked to return the value obtained.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string_2';
const VALUE_TEST_STRING_ELEMENT = 'value-string-002';
try{
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT, async function (err,data) {
        console.log('put success');
        kvStore.get('localDeviceId', KEY_TEST_STRING_ELEMENT, function (err,data) {
            console.log('get success');
        });
    })
}catch(e) {
    console.log('get e' + e);
}

get8+

get(deviceId: string, key: string): Promise&lt;boolean|string|number|Uint8Array&gt;

Obtains a string value that matches the specified device ID and key. This API uses a promise to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
key string Yes Key to match.

Return value

Type Description
Promise&lt;boolean|string|number|Uint8Array&gt; Promise used to return the string value that matches the given condition.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string_2';
const VALUE_TEST_STRING_ELEMENT = 'value-string-002';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT).then(async (data) => {
        console.log(' put success');
        kvStore.get('localDeviceId', KEY_TEST_STRING_ELEMENT).then((data) => {
            console.log('get success');
        }).catch((err) => {
            console.log('get fail ' + JSON.stringify(err));
        });
    }).catch((error) => {
        console.log('put error' + error);
    });
} catch (e) {
    console.log('Get e ' + e);
}

getEntries8+

getEntries(deviceId: string, keyPrefix: string, callback: AsyncCallback&lt;Entry[]&gt;): void

Obtains all KV pairs that match the specified device ID and key prefix. This API uses an asynchronous callback to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
keyPrefix string Yes Key prefix to match.
callback AsyncCallback&lt;Entry[]&gt; Yes Callback invoked to return the KV pairs obtained.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + entries);
    kvStore.putBatch(entries, async function (err,data) {
        console.log('putBatch success');
        kvStore.getEntries('localDeviceId', 'batch_test_string_key', function (err,entries) {
            console.log('getEntries success');
            console.log('entries.length: ' + entries.length);
            console.log('entries[0]: ' + JSON.stringify(entries[0]));
        });
    });
}catch(e) {
    console.log('PutBatch e ' + e);
}

getEntries8+

getEntries(deviceId: string, keyPrefix: string): Promise&lt;Entry[]&gt;

Obtains all KV pairs that match the specified device ID and key prefix. This API uses a promise to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
keyPrefix string Yes Key prefix to match.

Return value

Type Description
Promise&lt;Entry[]&gt; Promise used to return all the KV pairs that match the given condition.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + entries);
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
        kvStore.getEntries('localDeviceId', 'batch_test_string_key').then((entries) => {
            console.log('getEntries success');
            console.log('entries.length: ' + entries.length);
            console.log('entries[0]: ' + JSON.stringify(entries[0]));
            console.log('entries[0].value: ' + JSON.stringify(entries[0].value));
            console.log('entries[0].value.value: ' + entries[0].value.value);
        }).catch((err) => {
            console.log('getEntries fail ' + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log('putBatch fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('PutBatch e ' + e);
}

getEntries8+

getEntries(query: Query, callback: AsyncCallback&lt;Entry[]&gt;): void

Obtains the KV pairs that match the specified Query object. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.
callback AsyncCallback&lt;Entry[]&gt; Yes Callback invoked to return the KV pairs obtained.

Example

let kvStore;
try {
    var arr = new Uint8Array([21,31]);
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_bool_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.BYTE_ARRAY,
                value : arr
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + JSON.stringify(entries));
    kvStore.putBatch(entries, async function (err,data) {
        console.log('putBatch success');
        const query = new distributedData.Query();
        query.prefixKey("batch_test");
        query.deviceId('localDeviceId');
        kvStore.getEntries(query, function (err,entries) {
            console.log('getEntries success');
            console.log('entries.length: ' + entries.length);
            console.log('entries[0]: ' + JSON.stringify(entries[0]));
        });
    });
    console.log('GetEntries success');
}catch(e) {
    console.log('GetEntries e ' + e);
}

getEntries8+

getEntries(query: Query): Promise&lt;Entry[]&gt;

Obtains the KV pairs that match the specified Query object. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.

Return value

Type Description
Promise&lt;Entry[]&gt; Promise used to return the KV pairs that match the specified Query object.

Example

let kvStore;
try {
    var arr = new Uint8Array([21,31]);
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_bool_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.BYTE_ARRAY,
                value : arr
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + JSON.stringify(entries));
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
        const query = new distributedData.Query();
        query.prefixKey("batch_test");
        kvStore.getEntries(query).then((entries) => {
            console.log('getEntries success');
        }).catch((err) => {
            console.log('getEntries fail ' + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log('GetEntries putBatch fail ' + JSON.stringify(err))
    });
    console.log('GetEntries success');
}catch(e) {
    console.log('GetEntries e ' + e);
}

getEntries8+

getEntries(deviceId: string, query: Query, callback: AsyncCallback&lt;Entry[]&gt;): void

Obtains the KV pairs that match the specified device ID and Query object. This API uses an asynchronous callback to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
query Query Yes Query object to match.
callback AsyncCallback&lt;Entry[]&gt; Yes Callback invoked to return the KV pairs that match the specified device ID and Query object.

Example

let kvStore;
try {
    var arr = new Uint8Array([21,31]);
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_bool_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.BYTE_ARRAY,
                value : arr
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + JSON.stringify(entries));
    kvStore.putBatch(entries, async function (err,data) {
        console.log('putBatch success');
        var query = new distributedData.Query();
        query.deviceId('localDeviceId');
        query.prefixKey("batch_test");
        kvStore.getEntries('localDeviceId', query, function (err,entries) {
            console.log('getEntries success');
            console.log('entries.length: ' + entries.length);
            console.log('entries[0]: ' + JSON.stringify(entries[0]));
        })
    });
    console.log('GetEntries success');
}catch(e) {
    console.log('GetEntries e ' + e);
}

getEntries8+

getEntries(deviceId: string, query: Query): Promise&lt;Entry[]&gt;

Obtains the KV pairs that match the specified device ID and Query object. This API uses a promise to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
query Query Yes Query object to match.

Return value

Type Description
Promise&lt;Entry[]&gt; Promise used to return the KV pairs that match the specified device ID and Query object.

Example

let kvStore;
try {
    var arr = new Uint8Array([21,31]);
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_bool_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.BYTE_ARRAY,
                value : arr
            }
        }
        entries.push(entry);
    }
    console.log('entries: ' + JSON.stringify(entries));
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
        var query = new distributedData.Query();
        query.deviceId('localDeviceId');
        query.prefixKey("batch_test");
        kvStore.getEntries('localDeviceId', query).then((entries) => {
            console.log('getEntries success');
        }).catch((err) => {
            console.log('getEntries fail ' + JSON.stringify(err));
        });
    }).catch((err) => {
        console.log('putBatch fail ' + JSON.stringify(err));
    });
    console.log('GetEntries success');
}catch(e) {
    console.log('GetEntries e ' + e);
}

getResultSet8+

getResultSet(deviceId: string, keyPrefix: string, callback: AsyncCallback&lt;KvStoreResultSet&gt;): void

Obtains a KvStoreResultSet object that matches the specified device ID and key prefix. This API uses an asynchronous callback to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
keyPrefix string Yes Key prefix to match.
callback AsyncCallback&lt;KvStoreResultSet&gt; Yes Callback invoked to return the KvStoreResultSet object that matches the specified device ID and key prefix.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('localDeviceId', 'batch_test_string_key', async function (err, result) {
        console.log('getResultSet succeed.');
        resultSet = result;
        kvStore.closeResultSet(resultSet, function (err, data) {
            console.log('closeResultSet success');
        })
    });
}catch(e) {
    console.log('GetResultSet e ' + e);
}

getResultSet8+

getResultSet(deviceId: string, keyPrefix: string): Promise&lt;KvStoreResultSet&gt;

Obtains a KvStoreResultSet object that matches the specified device ID and key prefix. This API uses a promise to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
keyPrefix string Yes Key prefix to match.

Return value

Type Description
Promise&lt;KvStoreResultSet&gt; Promise used to return the KvStoreResultSet object that matches the specified device ID and key prefix.

Example

let kvStore;
try {
    let resultSet;
    kvStore.getResultSet('localDeviceId', 'batch_test_string_key').then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + JSON.stringify(err));
    });
    kvStore.closeResultSet(resultSet).then((err) => {
        console.log('closeResultSet success');
    }).catch((err) => {
        console.log('closeResultSet fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('GetResultSet e ' + e);
}

getResultSet8+

getResultSet(query: Query, callback: AsyncCallback&lt;KvStoreResultSet&gt;): void

Obtains a KvStoreResultSet object that matches the specified Query object. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.
callback AsyncCallback&lt;KvStoreResultSet&gt; Yes Callback invoked to return the KvStoreResultSet object obtained.

Example

let kvStore;
try {
    let resultSet;
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries, async function (err, data) {
        console.log('putBatch success');
        const query = new distributedData.Query();
        query.prefixKey("batch_test");
        query.deviceId('localDeviceId');
        kvStore.getResultSet(query, async function (err, result) {
            console.log('getResultSet succeed.');
            resultSet = result;
            kvStore.closeResultSet(resultSet, function (err, data) {
                console.log('closeResultSet success');
            })
        });
    });
} catch(e) {
    console.log('GetResultSet e ' + e);
}

getResultSet8+

getResultSet(query: Query): Promise&lt;KvStoreResultSet&gt;

Obtains a KvStoreResultSet object that matches the specified Query object. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.

Return value

Type Description
Promise&lt;KvStoreResultSet&gt; Promise used to return the KvStoreResultSet object that matches the specified Query object.

Example

let kvStore;
try {
    let resultSet;
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
    }).catch((err) => {
        console.log('putBatch fail ' + err);
    });
    const query = new distributedData.Query();
    query.deviceId('localDeviceId');
    query.prefixKey("batch_test");
    console.log("GetResultSet " + query.getSqlLike());
    kvStore.getResultSet(query).then((result) => {
        console.log('getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('getResultSet failed: ' + JSON.stringify(err));
    });
    kvStore.closeResultSet(resultSet).then((err) => {
        console.log('closeResultSet success');
    }).catch((err) => {
        console.log('closeResultSet fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('GetResultSet e ' + e);
}

getResultSet8+

getResultSet(deviceId: string, query: Query, callback: AsyncCallback&lt;KvStoreResultSet&gt;): void

Obtains a KvStoreResultSet object that matches the specified device ID and Query object. This API uses an asynchronous callback to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
query Query Yes Query object to match.
callback AsyncCallback&lt;KvStoreResultSet&gt; Yes Callback invoked to return the KvStoreResultSet object that matches the specified device ID and Query object.

Example

let kvStore;
try {
    let resultSet;
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries, async function (err, data) {
        console.log('putBatch success');
        const query = new distributedData.Query();
        query.prefixKey("batch_test");
        kvStore.getResultSet('localDeviceId', query, async function (err, result) {
            console.log('getResultSet succeed.');
            resultSet = result;
            kvStore.closeResultSet(resultSet, function (err, data) {
                console.log('closeResultSet success');
            })
        });
    });
} catch(e) {
    console.log('GetResultSet e ' + e);
}

getResultSet8+

getResultSet(deviceId: string, query: Query): Promise&lt;KvStoreResultSet&gt;

Obtains a KvStoreResultSet object that matches the specified device ID and Query object. This API uses a promise to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
query Query Yes Query object to match.

Return value

Type Description
Promise&lt;KvStoreResultSet&gt; Promise used to return the KvStoreResultSet object that matches the specified device ID and Query object.

Example

let kvStore;
try {
    let resultSet;
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries).then(async (err) => {
        console.log('GetResultSet putBatch success');
    }).catch((err) => {
        console.log('PutBatch putBatch fail ' + JSON.stringify(err));
    });
    const query = new distributedData.Query();
    query.prefixKey("batch_test");
    kvStore.getResultSet('localDeviceId', query).then((result) => {
        console.log('GetResultSet getResultSet succeed.');
        resultSet = result;
    }).catch((err) => {
        console.log('GetResultSet getResultSet failed: ' + JSON.stringify(err));
    });
    query.deviceId('localDeviceId');
    console.log("GetResultSet " + query.getSqlLike());
    kvStore.closeResultSet(resultSet).then((err) => {
        console.log('GetResultSet closeResultSet success');
    }).catch((err) => {
        console.log('GetResultSet closeResultSet fail ' + JSON.stringify(err));
    });

}catch(e) {
    console.log('GetResultSet e ' + e);
}

closeResultSet8+

closeResultSet(resultSet: KvStoreResultSet, callback: AsyncCallback&lt;void&gt;): void

Closes the KvStoreResultSet object obtained by DeviceKVStore.getResultSet. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
resultSet KvStoreResultSet Yes KvStoreResultSet object to close.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
try {
    console.log('CloseResultSet success');
    let resultSet = null;
    kvStore.closeResultSet(resultSet, function (err, data) {
        if (err == undefined) {
            console.log('closeResultSet success');
        } else {
            console.log('closeResultSet fail');
        }
    });
}catch(e) {
    console.log('CloseResultSet e ' + e);
}

closeResultSet8+

closeResultSet(resultSet: KvStoreResultSet): Promise&lt;void&gt;

Closes the KvStoreResultSet object obtained by DeviceKVStore.getResultSet. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
resultSet KvStoreResultSet Yes KvStoreResultSet object to close.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
try {
    console.log('CloseResultSet success');
    let resultSet = null;
    kvStore.closeResultSet(resultSet).then(() => {
        console.log('closeResultSet success');
    }).catch((err) => {
        console.log('closeResultSet fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('CloseResultSet e ' + e);
}

getResultSize8+

getResultSize(query: Query, callback: AsyncCallback&lt;number&gt;): void

Obtains the number of results that matches the specified Query object. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.
callback AsyncCallback&lt;number&gt; Yes Callback invoked to return the number of results obtained.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries, async function (err, data) {
        console.log('putBatch success');
        const query = new distributedData.Query();
        query.prefixKey("batch_test");
        query.deviceId('localDeviceId');
        kvStore.getResultSize(query, async function (err, resultSize) {
            console.log('getResultSet succeed.');
        });
    });
} catch(e) {
    console.log('GetResultSize e ' + e);
}

getResultSize8+

getResultSize(query: Query): Promise&lt;number&gt;

Obtains the number of results that matches the specified Query object. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
query Query Yes Query object to match.

Return value

Type Description
Promise&lt;number&gt; Promise used to return the number of results obtained.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
    }).catch((err) => {
        console.log('putBatch fail ' + JSON.stringify(err));
    });
    const query = new distributedData.Query();
    query.prefixKey("batch_test");
    query.deviceId('localDeviceId');
    kvStore.getResultSize(query).then((resultSize) => {
        console.log('getResultSet succeed.');
    }).catch((err) => {
        console.log('getResultSet failed: ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('GetResultSize e ' + e);
}

getResultSize8+

getResultSize(deviceId: string, query: Query, callback: AsyncCallback&lt;number&gt;): void;

Obtains the number of results that matches the specified device ID and Query object. This API uses an asynchronous callback to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
query Query Yes Query object to match.
callback AsyncCallback&lt;number&gt; Yes Callback invoked to return the number of results obtained.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries, async function (err, data) {
        console.log('putBatch success');
        const query = new distributedData.Query();
        query.prefixKey("batch_test");
        kvStore.getResultSize('localDeviceId', query, async function (err, resultSize) {
            console.log('getResultSet succeed.');
        });
    });
} catch(e) {
    console.log('GetResultSize e ' + e);
}

getResultSize8+

getResultSize(deviceId: string, query: Query): Promise&lt;number&gt;

Obtains the number of results that matches the specified device ID and Query object. This API uses a promise to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
query Query Yes Query object to match.

Return value

Type Description
Promise&lt;number&gt; Promise used to return the number of results obtained.

Example

let kvStore;
try {
    let entries = [];
    for (var i = 0; i < 10; i++) {
        var key = 'batch_test_string_key';
        var entry = {
            key : key + i,
            value : {
                type : distributedData.ValueType.STRING,
                value : 'batch_test_string_value'
            }
        }
        entries.push(entry);
    }
    kvStore.putBatch(entries).then(async (err) => {
        console.log('putBatch success');
    }).catch((err) => {
        console.log('putBatch fail ' + JSON.stringify(err));
    });
    var query = new distributedData.Query();
    query.prefixKey("batch_test");
    kvStore.getResultSize('localDeviceId', query).then((resultSize) => {
        console.log('getResultSet succeed.');
    }).catch((err) => {
        console.log('getResultSet failed: ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('GetResultSize e ' + e);
}

removeDeviceData8+

removeDeviceData(deviceId: string, callback: AsyncCallback&lt;void&gt;): void

Deletes data of the specified device from this KV store. This API uses an asynchronous callback to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.
callback AsyncCallback&lt;void&gt; Yes Callback invoked to return the result.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string';
const VALUE_TEST_STRING_ELEMENT = 'value-string-001';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT, async function (err,data) {
        console.log('RemoveDeviceData  put success');
        const deviceid = 'no_exist_device_id';
        kvStore.removeDeviceData(deviceid, async function (err,data) {
            if (err == undefined) {
                console.log('removeDeviceData success');
            } else {
                console.log('removeDeviceData fail');
                kvStore.get('localDeviceId', KEY_TEST_STRING_ELEMENT, async function (err,data) {
                    console.log('RemoveDeviceData get success');
                });
            }
        });
    });
}catch(e) {
    console.log('RemoveDeviceData e ' + e);
}

removeDeviceData8+

removeDeviceData(deviceId: string): Promise&lt;void&gt;

Deletes data of the specified device from this KV store. This API uses a promise to return the result. > NOTE > > deviceId is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications. > For details about how to obtain deviceId, see sync().

System capability: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore

Parameters

Name Type Mandatory Description
deviceId string Yes ID of the target device.

Return value

Type Description
Promise&lt;void&gt; Promise that returns no value.

Example

let kvStore;
const KEY_TEST_STRING_ELEMENT = 'key_test_string';
const VALUE_TEST_STRING_ELEMENT = 'value-string-001';
try {
    kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT).then((err) => {
        console.log('RemoveDeviceData put success');
    }).catch((err) => {
        console.log('RemoveDeviceData put fail ' + JSON.stringify(err));
    });
    const deviceid = 'no_exist_device_id';
    kvStore.removeDeviceData(deviceid).then((err) => {
        console.log('removeDeviceData success');
    }).catch((err) => {
        console.log('removeDeviceData fail ' + JSON.stringify(err));
    });
    kvStore.get('localDeviceId', KEY_TEST_STRING_ELEMENT).then((data) => {
        console.log('RemoveDeviceData get success data:' + data);
    }).catch((err) => {
        console.log('RemoveDeviceData get fail ' + JSON.stringify(err));
    });
}catch(e) {
    console.log('RemoveDeviceData e ' + e);
}

sync8+

sync(deviceIds: string[], mode: SyncMode, delayMs?: number): void

Synchronizes the KV store manually.

NOTE

deviceIds is the networkId in DeviceInfo, which is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
deviceIds string[] Yes networkIds of the devices to be synchronized.
mode SyncMode Yes Synchronization mode.
delayMs number No Allowed synchronization delay time, in ms. The default value is 0.

Example

import deviceManager from '@ohos.distributedHardware.deviceManager';

let devManager;
let kvStore;
const KEY_TEST_SYNC_ELEMENT = 'key_test_sync';
const VALUE_TEST_SYNC_ELEMENT = 'value-string-001';
// create deviceManager
deviceManager.createDeviceManager('bundleName', (err, value) => {
  if (!err) {
    devManager = value;
    let deviceIds = [];
    if (devManager != null) {
      var devices = devManager.getTrustedDeviceListSync();
      for (var i = 0; i < devices.length; i++) {
        deviceIds[i] = devices[i].networkId;
      }
    }
    try {
      kvStore.on('syncComplete', function (data) {
        console.log('Sync dataChange');
      });
      kvStore.put(KEY_TEST_SYNC_ELEMENT + 'testSync101', VALUE_TEST_SYNC_ELEMENT, function (err, data) {
        if (err != undefined) {
          console.log("put err: " + JSON.stringify(err));
          return;
        }
        console.log('Succeeded in putting data');
        const mode = distributedData.SyncMode.PULL_ONLY;
        kvStore.sync(deviceIds, mode, 1000);
      });
    } catch (e) {
      console.log('Sync e' + e);
    }
  }
});

on(‘dataChange’)8+

on(event: ‘dataChange’, type: SubscribeType, listener: Callback&lt;ChangeNotification&gt;): void

Subscribes to data changes of the specified type.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to subscribe to. The value is dataChange, which indicates a data change event.
type SubscribeType Yes Type of data change.
listener Callback&lt;ChangeNotification&gt; Yes Callback invoked to return a data change event.

Example

let kvStore;
kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_LOCAL, function (data) {
    console.log("dataChange callback call data: " + JSON.stringify(data));
});

on(‘syncComplete’)8+

on(event: ‘syncComplete’, syncCallback: Callback&lt;Array&lt;[string, number]&gt;&gt;): void

Subscribes to synchronization complete events.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to subscribe to. The value is syncComplete, which indicates a synchronization complete event.
syncCallback Callback&lt;Array&lt;[string, number]&gt;&gt; Yes Callback invoked to return a synchronization complete event.

Example

let kvStore;
const KEY_TEST_FLOAT_ELEMENT = 'key_test_float';
const VALUE_TEST_FLOAT_ELEMENT = 321.12;
try {
    kvStore.on('syncComplete', function (data) {
        console.log('syncComplete ' + data)
    });
    kvStore.put(KEY_TEST_FLOAT_ELEMENT, VALUE_TEST_FLOAT_ELEMENT).then((data) => {
        console.log('syncComplete put success');
    }).catch((error) => {
        console.log('syncComplete put fail ' + error);
    });
}catch(e) {
    console.log('syncComplete put e ' + e);
}

off(‘dataChange’)8+

off(event:‘dataChange’, listener?: Callback&lt;ChangeNotification&gt;): void

Unsubscribes from data changes.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to unsubscribe from. The value is dataChange, which indicates a data change event.
listener Callback&lt;ChangeNotification&gt; No Callback for the data change event. If the callback is not specified, all subscriptions to the data change event are canceled.

Example

let kvStore;
class KvstoreModel {
    call(data) {
        console.log("dataChange: " + data);
    }
    subscribeDataChange() {
        if (kvStore != null) {
            kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_REMOTE, this.call);
        }
    }
    unsubscribeDataChange() {
        if (kvStore != null) {
            kvStore.off('dataChange', this.call);
        }
    }
}

off(‘syncComplete’)8+

off(event: ‘syncComplete’, syncCallback?: Callback&lt;Array&lt;[string, number]&gt;&gt;): void

Unsubscribes from synchronization complete events.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Parameters

Name Type Mandatory Description
event string Yes Event to unsubscribe from. The value is syncComplete, which indicates a synchronization complete event.
syncCallback Callback&lt;Array&lt;[string, number]&gt;&gt; No Callback for the synchronization complete event. If the callback is not specified, all subscriptions to the synchronization complete event are canceled.

Example

let kvStore;
class KvstoreModel {
    call(data) {
        console.log("syncComplete: " + data);
    }
    subscribeSyncComplete() {
        if (kvStore != null) {
            kvStore.on('syncComplete', this.call);
        }
    }
    unsubscribeSyncComplete() {
        if (kvStore != null) {
            kvStore.off('syncComplete', this.call);
        }
    }
}

SyncMode

Enumerates the synchronization modes.

System capability: SystemCapability.DistributedDataManager.KVStore.Core

Name Value Description
PULL_ONLY 0 Pull data from the peer end to the local end only.
PUSH_ONLY 1 Push data from the local end to the peer end only.
PUSH_PULL 2 Push data from the local end to the peer end and then pull data from the peer end to the local end.

你可能感兴趣的鸿蒙文章

harmony 鸿蒙APIs

harmony 鸿蒙System Common Events (To Be Deprecated Soon)

harmony 鸿蒙System Common Events

harmony 鸿蒙API Reference Document Description

harmony 鸿蒙Enterprise Device Management Overview (for System Applications Only)

harmony 鸿蒙BundleStatusCallback

harmony 鸿蒙@ohos.bundle.innerBundleManager (innerBundleManager)

harmony 鸿蒙@ohos.distributedBundle (Distributed Bundle Management)

harmony 鸿蒙@ohos.bundle (Bundle)

harmony 鸿蒙@ohos.enterprise.EnterpriseAdminExtensionAbility (EnterpriseAdminExtensionAbility)

0  赞
  • 所属分类： 后端技术
  • 本文标签：
  • 版权声明： 原创文章如转载，请注明本文链接: https://m.seaxiang.com/blog/6f9b8ceffc384fe0a37088a75b501dfc
热门推荐
标签云
Linux Java Spring Spring Boot docker 大数据 前端 生活 maven golang 软件 spring cloud fintech mac vscode 其他 区块链 以太坊 V神 开发者 技术 股票 git greenplum 分布式事务 chrome mysql flink kafka 设计模式 原理 鸿蒙 seo
最新文章
本文目录