@ohos.data.dataSharePredicates (DataShare Predicates)

DataSharePredicates provides a filter object to query data in a database by using DataShare APIs. It is often used to update, delete, and query data.

The APIs provided by DataSharePredicates correspond to the filter criteria of the database. Before using the APIs, you need to have basic database knowledge.

NOTE

• The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.

• The APIs of this module can be used only in the stage model.

Modules to Import

import { dataSharePredicates } from '@kit.ArkData';

DataSharePredicates

Provides APIs for setting different DataSharePredicates objects. This type is not multi-thread safe. If a DataSharePredicates instance is operated by multiple threads at the same time in an application, use a lock for it.

equalTo¹⁰⁺

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

Creates a DataSharePredicates object to search for the records in the specified column that are equal to the given value.

Currently, only the relational database (RDB) and key-value database (KVDB, schema) support this DataSharePredicates object.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

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

Return value

Type	Description
DataSharePredicates	DataSharePredicates object created.

Example

let predicates = new dataSharePredicates.DataSharePredicates()
predicates.equalTo("NAME", "Rose")

and¹⁰⁺

and(): DataSharePredicates

Creates a DataSharePredicates object to add the AND condition.

Currently, only the RDB and KVDB (schema) support this DataSharePredicates object.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Return value

Type	Description
DataSharePredicates	DataSharePredicates object with the AND condition.

Example

let predicates = new dataSharePredicates.DataSharePredicates()
predicates.equalTo("NAME", "lisi")
    .and()
    .equalTo("SALARY", 200.5)

orderByAsc¹⁰⁺

orderByAsc(field: string): DataSharePredicates

Creates a DataSharePredicates object that sorts records in ascending order.

Currently, only the RDB and KVDB (schema) support this DataSharePredicates object.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

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

Return value

Type	Description
DataSharePredicates	DataSharePredicates object created.

Example

let predicates = new dataSharePredicates.DataSharePredicates()
predicates.orderByAsc("AGE")

orderByDesc¹⁰⁺

orderByDesc(field: string): DataSharePredicates

Creates a DataSharePredicates object that sorts data in descending order.

Currently, only the RDB and KVDB (schema) support this DataSharePredicates object.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

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

Return value

Type	Description
DataSharePredicates	DataSharePredicates object created.

Example

let predicates = new dataSharePredicates.DataSharePredicates()
predicates.orderByDesc("AGE")

limit¹⁰⁺

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

Creates a DataSharePredicates object to specify the number of records in the result and the start position.

Currently, only the RDB and KVDB (schema) support this DataSharePredicates object.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

Name	Type	Mandatory	Description
total	number	Yes	Number of records. The value should be a positive integer. If a value less than or equal to 0 is specified, the number of records is not limited.
offset	number	Yes	Start position. The value should be a positive integer. If a value less than or equal to 0 is specified, the query result is returned from the first element.

Return value

Type	Description
DataSharePredicates	DataSharePredicates object created.

Example

let predicates = new dataSharePredicates.DataSharePredicates()
predicates.equalTo("NAME", "Rose").limit(10, 3)

in¹⁰⁺

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

Creates a DataSharePredicates object to search for the records in the specified column that are within the specified range.

Currently, only the RDB and KVDB (schema) support this DataSharePredicates object.

System capability: SystemCapability.DistributedDataManager.DataShare.Core

Parameters

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

Return value

Type	Description
DataSharePredicates	DataSharePredicates object created.

Example

let predicates = new dataSharePredicates.DataSharePredicates()
predicates.in("AGE", [18, 20])

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