A relational database (RDB) store allows you to operate local data with or without native SQL statements based on SQLite.
A relational database (RDB) store allows you to manage local data with or without native SQL statements based on SQLite.
## Available APIs
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@@ -21,11 +21,11 @@ The table below describes the APIs available for creating and deleting an RDB st
### Managing Data in an RDB Store
The RDB provides APIs for inserting, deleting, updating, and querying data in the local RDB store.
The **RDB** module provides APIs for inserting, deleting, updating, and querying data in a local RDB store.
-**Inserting Data**
The RDB provides APIs for inserting data through a **ValuesBucket** in a data table. If the data is inserted, the row ID of the data inserted will be returned; otherwise, **-1** will be returned.
The **RDB** module provides APIs for inserting data through a **ValuesBucket** in a data table. If the data is inserted, the row ID of the data inserted will be returned; otherwise, **-1** will be returned.
**Table 2** API for inserting data
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@@ -41,7 +41,7 @@ The RDB provides APIs for inserting, deleting, updating, and querying data in th
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | update(values:ValuesBucket,rdbPredicates:RdbPredicates):Promise\<number> | Updates data based on the specified **RdbPredicates** object. This API uses a promise to return the result.<br>Return value: number of rows updated.<br>- **values**: data to update, which is stored in **ValuesBucket**.<br>- **rdbPredicates**: conditions for updating data.|
| RdbStore | update(values:ValuesBucket,rdbPredicates:RdbPredicates):Promise\<number> | Updates data based on the specified **RdbPredicates** object. This API uses a promise to return the result.<br>Return value: number of rows updated.<br>- **values**: data to update, which is stored in **ValuesBucket**.<br>- **rdbPredicates**: conditions for updating data.|
-**Deleting Data**
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@@ -51,7 +51,7 @@ The RDB provides APIs for inserting, deleting, updating, and querying data in th
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | delete(rdbPredicates:RdbPredicates):Promise\<number> | Deletes data from the RDB store based on the specified **RdbPredicates** object. This API uses a promise to return the result.<br>Return value: number of rows updated.<br>- **rdbPredicates**: conditions for deleting data.|
| RdbStore | delete(rdbPredicates:RdbPredicates):Promise\<number> | Deletes data from the RDB store based on the specified **RdbPredicates** object. This API uses a promise to return the result.<br>Return value: number of rows updated.<br>- **rdbPredicates**: conditions for deleting data.|
-**Querying data**
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@@ -69,19 +69,19 @@ The RDB provides APIs for inserting, deleting, updating, and querying data in th
### Using Predicates
The RDB provides **RdbPredicates** for you to set database operation conditions.
The **RDB** module provides **RdbPredicates** for you to set database operation conditions.
The following lists common predicates. For more information about predicates, see [**RdbPredicates**](../reference/apis/js-apis-data-rdb.md#rdbpredicates).
The table below lists common predicates. For more information about predicates, see [**RdbPredicates**](../reference/apis/js-apis-data-rdb.md#rdbpredicates).
**Table 6** APIs for using RDB store predicates
| Class| API| Description|
| -------- | -------- | -------- |
| RdbPredicates | equalTo(field:string,value:ValueType):RdbPredicates | Sets an **RdbPredicates**to match the field with data type **ValueType** and value equal to the specified value.<br>- **field**: column name in the database table.<br>- **value**: value to match the **RdbPredicates**.<br>- **RdbPredicates**: **RdbPredicates** object that matches the specified field. |
| RdbPredicates | notEqualTo(field:string,value:ValueType):RdbPredicates | Sets an **RdbPredicates**to match the field with data type **ValueType** and value not equal to the specified value.<br>- **field**: column name in the database table.<br>- **value**: value to match the **RdbPredicates**.<br>- **RdbPredicates**: **RdbPredicates** object that matches the specified field. |
| RdbPredicates | or():RdbPredicates | Adds the OR condition to the **RdbPredicates**.<br>- **RdbPredicates**: **RdbPredicates** with the OR condition.|
| RdbPredicates | and():RdbPredicates | Adds the AND condition to the **RdbPredicates**.<br>- **RdbPredicates**: **RdbPredicates** with the AND condition.|
| RdbPredicates | contains(field:string,value:string):RdbPredicats | Sets an **RdbPredicates**to match a string that contains the specified value.<br>- **field**: column name in the database table.<br>- **value**: value to match the **RdbPredicates**.<br>- **RdbPredicates**: **RdbPredicates** object that matches the specified field. |
| RdbPredicates | equalTo(field:string,value:ValueType):RdbPredicates | Sets an **RdbPredicates**object to match the field with data type **ValueType** and value equal to the specified value.<br>- **field**: column name in the database table.<br>- **value**: value to match the **RdbPredicates**.<br>- **RdbPredicates**: **RdbPredicates** object created.|
| RdbPredicates | notEqualTo(field:string,value:ValueType):RdbPredicates | Sets an **RdbPredicates**object to match the field with data type **ValueType** and value not equal to the specified value.<br>- **field**: column name in the database table.<br>- **value**: value to match the **RdbPredicates**.<br>- **RdbPredicates**: **RdbPredicates** object created.|
| RdbPredicates | or():RdbPredicates | Adds the OR condition to the **RdbPredicates** object.<br>- **RdbPredicates**: **RdbPredicates** with the OR condition.|
| RdbPredicates | and():RdbPredicates | Adds the AND condition to the **RdbPredicates** object.<br>- **RdbPredicates**: **RdbPredicates** with the AND condition.|
| RdbPredicates | contains(field:string,value:string):RdbPredicats | Sets an **RdbPredicates**object to match a string that contains the specified value.<br>- **field**: column name in the database table.<br>- **value**: value to match the **RdbPredicates**.<br>- **RdbPredicates**: **RdbPredicates** object created.|
