harmony 鸿蒙@ohos.data.dataAbility (DataAbility Predicates)

2022-08-09
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@ohos.data.dataAbility (DataAbility Predicates)

DataAbility provides APIs for creating predicates, which implement different query methods for relational database (RDB) stores.

NOTE

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.

Modules to Import

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

dataAbility.createRdbPredicates

createRdbPredicates(name: string, dataAbilityPredicates: DataAbilityPredicates): rdb.RdbPredicates

Creates an RdbPredicates object from a DataAbilityPredicates object.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
name	string	Yes	Name of a database table.
dataAbilityPredicates	DataAbilityPredicates	Yes	DataAbilityPredicates object.

Return value

Type	Description
rdb.RdbPredicates	RdbPredicates object created.

Example

  let dataAbilityPredicates = new dataAbility.DataAbilityPredicates()
  dataAbilityPredicates.equalTo("NAME", "Rose")
  let predicates = dataAbility.createRdbPredicates("EMPLOYEE", dataAbilityPredicates)

DataAbilityPredicates

Provides predicates for implementing diverse query methods.

equalTo

equalTo(field: string, value: ValueType): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field with data type ValueType and value equal to the specified value.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	ValueType	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.equalTo("NAME", "lisi")

notEqualTo

notEqualTo(field: string, value: ValueType): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field with data type ValueType and value not equal to the specified value.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	ValueType	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.notEqualTo("NAME", "lisi")

beginWrap

beginWrap(): DataAbilityPredicates

Adds a left parenthesis to this DataAbilityPredicates.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object with a left parenthesis.

Example

  dataAbilityPredicates.equalTo("NAME", "lisi")
      .beginWrap()
      .equalTo("AGE", 18)
      .or()
      .equalTo("SALARY", 200.5)
      .endWrap()

endWrap

endWrap(): DataAbilityPredicates

Adds a right parenthesis to this DataAbilityPredicates.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object with a right parenthesis.

Example

  dataAbilityPredicates.equalTo("NAME", "lisi")
      .beginWrap()
      .equalTo("AGE", 18)
      .or()
      .equalTo("SALARY", 200.5)
      .endWrap()

or

or(): DataAbilityPredicates

Adds the OR condition to this DataAbilityPredicates.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object with the OR condition.

Example

  dataAbilityPredicates.equalTo("NAME", "Lisa")
      .or()
      .equalTo("NAME", "Rose")

and

and(): DataAbilityPredicates

Adds the AND condition to this DataAbilityPredicates.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object with the AND condition.

Example

  dataAbilityPredicates.equalTo("NAME", "Lisa")
      .and()
      .equalTo("SALARY", 200.5)

contains

contains(field: string, value: string): DataAbilityPredicates

Sets a DataAbilityPredicates object to match a string containing the specified value.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	string	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.contains("NAME", "os")

beginsWith

beginsWith(field: string, value: string): DataAbilityPredicates

Sets a DataAbilityPredicates object to match a string that starts with the specified value.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	string	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.beginsWith("NAME", "os")

endsWith

endsWith(field: string, value: string): DataAbilityPredicates

Sets a DataAbilityPredicates object to match a string that ends with the specified value.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	string	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.endsWith("NAME", "se")

isNull

isNull(field: string): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field whose value is null.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.isNull("NAME")

isNotNull

isNotNull(field: string): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field whose value is not null.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.isNotNull("NAME")

like

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

Sets a DataAbilityPredicates object to match a string that is similar to the specified value.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	string	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.like("NAME", "%os%")

glob

glob(field: string, value: string): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the specified string.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	string	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.glob("NAME", "?h*g")

between

between(field: string, low: ValueType, high: ValueType): DataAbilityPredicates

Sets a DataAbilityPredicates object to match a field whose data type is ValueType and value is within the specified range.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
low	ValueType	Yes	Minimum value to match the DataAbilityPredicates.
high	ValueType	Yes	Maximum value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.between("AGE", 10, 50)

notBetween

notBetween(field: string, low: ValueType, high: ValueType): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field with data type ValueType and value out of the specified range.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
low	ValueType	Yes	Minimum value to match the DataAbilityPredicates.
high	ValueType	Yes	Maximum value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.notBetween("AGE", 10, 50)

greaterThan

greaterThan(field: string, value: ValueType): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field with data type ValueType and value greater than the specified value.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	ValueType	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.greaterThan("AGE", 18)

lessThan

lessThan(field: string, value: ValueType): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field with data type ValueType and value less than the specified value.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	ValueType	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.lessThan("AGE", 20)

greaterThanOrEqualTo

greaterThanOrEqualTo(field: string, value: ValueType): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field with data type ValueType and value greater than or equal to the specified value.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	ValueType	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.greaterThanOrEqualTo("AGE", 18)

lessThanOrEqualTo

lessThanOrEqualTo(field: string, value: ValueType): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field with data type ValueType and value less than or equal to the specified value.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	ValueType	Yes	Value to match the DataAbilityPredicates.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.lessThanOrEqualTo("AGE", 20)

orderByAsc

orderByAsc(field: string): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the column with values sorted in ascending order.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.orderByAsc("NAME")

orderByDesc

orderByDesc(field: string): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the column with values sorted in descending order.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.orderByDesc("AGE")

distinct

distinct(): DataAbilityPredicates

Sets a DataAbilityPredicates object to filter out duplicate records.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that can filter out duplicate records.

Example

  dataAbilityPredicates.equalTo("NAME", "Rose").distinct()

limitAs

limitAs(value: number): DataAbilityPredicates

Set a DataAbilityPredicates object to specify the maximum number of records.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
value	number	Yes	Maximum number of records.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that specifies the maximum number of records.

Example

  dataAbilityPredicates.equalTo("NAME", "Rose").limitAs(3)

offsetAs

offsetAs(rowOffset: number): DataAbilityPredicates

Sets a DataAbilityPredicates object to specify the start position of the returned result.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
rowOffset	number	Yes	Number of rows to offset from the beginning. The value is a positive integer.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that specifies the start position of the returned result.

Example

  dataAbilityPredicates.equalTo("NAME", "Rose").offsetAs(3)

groupBy

groupBy(fields: Array<string>): DataAbilityPredicates

Sets a DataAbilityPredicates object to group rows that have the same value into summary rows.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
fields	Array<string>	Yes	Names of columns to group.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that groups rows with the same value.

Example

  dataAbilityPredicates.groupBy(["AGE", "NAME"])

indexedBy

indexedBy(field: string): DataAbilityPredicates

Sets a DataAbilityPredicates object to specify the index column.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
indexName	string	Yes	Name of the index column.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that specifies the index column.

Example

  dataAbilityPredicates.indexedBy("SALARY_INDEX")

in

in(field: string, value: Array<ValueType>): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field with data type Array<ValueType> and value within the specified range.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	Array<ValueType>	Yes	Array of ValueTypes to match.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.in("AGE", [18, 20])

notIn

notIn(field: string, value: Array<ValueType>): DataAbilityPredicates

Sets a DataAbilityPredicates object to match the field with data type Array<ValueType> and value out of the specified range.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
field	string	Yes	Column name in the table.
value	Array<ValueType>	Yes	Array of ValueTypes to match.

Return value

Type	Description
DataAbilityPredicates	DataAbilityPredicates object that matches the specified field.

Example

  dataAbilityPredicates.notIn("NAME", ["Lisa", "Rose"])

ValueType

Enumerates the value types.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Type	Description
number	The value is a number.
string	The value is a string.
boolean	The value is of Boolean type.

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harmony 鸿蒙@ohos.data.dataAbility (DataAbility Predicates)

@ohos.data.dataAbility (DataAbility Predicates)

Modules to Import

dataAbility.createRdbPredicates

DataAbilityPredicates

equalTo

notEqualTo

beginWrap

endWrap

or

and

contains

beginsWith

endsWith

isNull

isNotNull

like

glob

between

notBetween

greaterThan

lessThan

greaterThanOrEqualTo

lessThanOrEqualTo

orderByAsc

orderByDesc

distinct

limitAs

offsetAs

groupBy

indexedBy

in

notIn

ValueType

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