Skip to content

D
Docs

OpenHarmony / Docs
大约 2 年 前同步成功

通知 161
Star 293
Fork 28
D
Docs
“8a93642044319b3f905f708a4b77da515388f8a2”上不存在“test/git@gitcode.net:openanolis/dragonwell8_jdk.git”
未验证 提交 4e64c41a 编写于 作者: 葛 葛亚芳 提交者： Gitee
浏览文件
操作

update en/application-dev/database/database-relational-guidelines.md. 

Signed-off-by: N@ge-yafang <geyafang@huawei.com>
上级 fd848b4b
隐藏空白更改
内联 并排
Showing with 91 addition and 96 deletion
en/application-dev/database/database-relational-guidelines.md
浏览文件 @ 4e64c41a
......@@ -13,12 +13,12 @@ The following table describes the APIs available for creating and deleting an RD
**Table 1** APIs for creating and deleting an RDB store
| API| Description|
| -------- | -------- |
|getRdbStore(config:&nbsp;StoreConfig,&nbsp;version:&nbsp;number,&nbsp;callback:&nbsp;AsyncCallback&lt;RdbStore&gt;):&nbsp;void | Obtains an RDB store. This method uses a callback to return the result. You can set parameters for the RDB store based on service requirements, and then call APIs to perform data operations.<br>-&nbsp;**config**: configuration of the RDB store.<br>-&nbsp;**version**: RDB version.<br>-&nbsp;**callback**: callback invoked to return the RDB store obtained.|
|getRdbStore(config:&nbsp;StoreConfig,&nbsp;version:&nbsp;number):&nbsp;Promise&lt;RdbStore&gt; | Obtains an RDB store. This method uses a promise to return the result. You can set parameters for the RDB store based on service requirements, and then call APIs to perform data operations.<br>-&nbsp;**config**: configuration of the RDB store.<br>-&nbsp;**version**: RDB version.|
|deleteRdbStore(name:&nbsp;string,&nbsp;callback:&nbsp;AsyncCallback&lt;void&gt;):&nbsp;void | Deletes an RDB store. This method uses a callback to return the result. <br>-&nbsp;**name**: RDB store to delete.<br>-&nbsp;**callback**: callback invoked to return the result.|
| deleteRdbStore(name:&nbsp;string):&nbsp;Promise&lt;void&gt; | Deletes an RDB store. This method uses a promise to return the result.<br>-&nbsp;**name**: RDB store to delete.|
| API | Description |
| ------------------------------------------------------------ | ------------------------------------------------------------ |
| getRdbStore(config:&nbsp;StoreConfig,&nbsp;version:&nbsp;number,&nbsp;callback:&nbsp;AsyncCallback&lt;RdbStore&gt;):&nbsp;void | Obtains an RDB store. This method uses a callback to return the result. You can set parameters for the RDB store based on service requirements, and then call APIs to perform data operations.<br>-&nbsp;**config**: configuration of the RDB store.<br>-&nbsp;**version**: RDB version.<br>-&nbsp;**callback**: callback invoked to return the RDB store obtained. |
| getRdbStore(config:&nbsp;StoreConfig,&nbsp;version:&nbsp;number):&nbsp;Promise&lt;RdbStore&gt; | Obtains an RDB store. This method uses a promise to return the result. You can set parameters for the RDB store based on service requirements, and then call APIs to perform data operations.<br>-&nbsp;**config**: configuration of the RDB store.<br>-&nbsp;**version**: RDB version. |
| deleteRdbStore(name:&nbsp;string,&nbsp;callback:&nbsp;AsyncCallback&lt;void&gt;):&nbsp;void | Deletes an RDB store. This method uses a callback to return the result. <br>-&nbsp;**name**: RDB store to delete.<br>-&nbsp;**callback**: callback invoked to return the result. |
| deleteRdbStore(name:&nbsp;string):&nbsp;Promise&lt;void&gt; | Deletes an RDB store. This method uses a promise to return the result.<br>-&nbsp;**name**: RDB store to delete. |
### Managing Data in an RDB Store
......@@ -30,10 +30,10 @@ The RDB provides APIs for inserting, deleting, updating, and querying data in th
**Table 2** APIs for inserting data
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | insert(name:&nbsp;string,&nbsp;values:&nbsp;ValuesBucket,&nbsp;callback:&nbsp;AsyncCallback&lt;number&gt;):void | Inserts a row of data into a table. This method uses a callback to return the result.<br>-&nbsp;**name**: name of the target table.<br>-&nbsp;**values**: data to be inserted into the table.<br>-&nbsp;**callback**: callback invoked to return the result. If the operation is successful, the row ID will be returned. Otherwise, **-1** will be returned.|
| RdbStore | insert(name:&nbsp;string,&nbsp;values:&nbsp;ValuesBucket):&nbsp;Promise&lt;number&gt; | Inserts a row of data into a table. This method uses a promise to return the result.<br>-&nbsp;**name**: name of the target table.<br>-&nbsp;**values**: data to be inserted into the table.|
| Class | API | Description |
| -------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
| RdbStore | insert(name:&nbsp;string,&nbsp;values:&nbsp;ValuesBucket,&nbsp;callback:&nbsp;AsyncCallback&lt;number&gt;):void | Inserts a row of data into a table. This method uses a callback to return the result.<br>-&nbsp;**name**: name of the target table.<br>-&nbsp;**values**: data to be inserted into the table.<br>-&nbsp;**callback**: callback invoked to return the result. If the operation is successful, the row ID will be returned. Otherwise, **-1** will be returned. |
| RdbStore | insert(name:&nbsp;string,&nbsp;values:&nbsp;ValuesBucket):&nbsp;Promise&lt;number&gt; | Inserts a row of data into a table. This method uses a promise to return the result.<br>-&nbsp;**name**: name of the target table.<br>-&nbsp;**values**: data to be inserted into the table. |
- **Updating data**
......@@ -41,10 +41,10 @@ The RDB provides APIs for inserting, deleting, updating, and querying data in th
**Table 3** APIs for updating data
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | update(values:&nbsp;ValuesBucket,&nbsp;rdbPredicates:&nbsp;RdbPredicates,&nbsp;callback:&nbsp;AsyncCallback&lt;number&gt;):void | Updates data in the RDB store based on the specified **RdbPredicates** object. This method uses a callback to return the result.<br>-&nbsp;**values**: data to update, which is stored in a **ValuesBucket**.<br>-&nbsp;**rdbPredicates**: conditions for updating data.<br>-&nbsp;**callback**: callback invoked to return the number of rows updated.|
| RdbStore | update(values:&nbsp;ValuesBucket,&nbsp;rdbPredicates:&nbsp;RdbPredicates):&nbsp;Promise | Updates data in the RDB store based on the specified **RdbPredicates** object. This method uses a promise to return the result.<br>-&nbsp;**values**: data to update, which is stored in a **ValuesBucket**.<br>-&nbsp;**rdbPredicates**: conditions for updating data.|
| Class | API | Description |
| -------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
| RdbStore | update(values:&nbsp;ValuesBucket,&nbsp;rdbPredicates:&nbsp;RdbPredicates,&nbsp;callback:&nbsp;AsyncCallback&lt;number&gt;):void | Updates data in the RDB store based on the specified **RdbPredicates** object. This method uses a callback to return the result.<br>-&nbsp;**values**: data to update, which is stored in a **ValuesBucket**.<br>-&nbsp;**rdbPredicates**: conditions for updating data.<br>-&nbsp;**callback**: callback invoked to return the number of rows updated. |
| RdbStore | update(values:&nbsp;ValuesBucket,&nbsp;rdbPredicates:&nbsp;RdbPredicates):&nbsp;Promise\<number> | Updates data in the RDB store based on the specified **RdbPredicates** object. This method uses a promise to return the result.<br>-&nbsp;**values**: data to update, which is stored in a **ValuesBucket**.<br>-&nbsp;**rdbPredicates**: conditions for updating data. |
- **Deleting data**
......@@ -52,10 +52,10 @@ The RDB provides APIs for inserting, deleting, updating, and querying data in th
**Table 4** APIs for deleting data
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | delete(rdbPredicates:&nbsp;RdbPredicates,&nbsp;callback:&nbsp;AsyncCallback&lt;number&gt;):void | Deletes data from the RDB store based on the specified **RdbPredicates** object. This method uses a callback to return the result.<br>-&nbsp;**rdbPredicates**: conditions for deleting data.<br>-&nbsp;**callback**: callback invoked to return the number of rows deleted.|
| RdbStore | delete(rdbPredicates:&nbsp;RdbPredicates):&nbsp;Promise | Deletes data from the RDB store based on the specified **RdbPredicates** object. This method uses a promise to return the result.<br>-&nbsp;**rdbPredicates**: conditions for deleting data.|
| Class | API | Description |
| -------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
| RdbStore | delete(rdbPredicates:&nbsp;RdbPredicates,&nbsp;callback:&nbsp;AsyncCallback&lt;number&gt;):void | Deletes data from the RDB store based on the specified **RdbPredicates** object. This method uses a callback to return the result.<br>-&nbsp;**rdbPredicates**: conditions for deleting data.<br>-&nbsp;**callback**: callback invoked to return the number of rows deleted. |
| RdbStore | delete(rdbPredicates:&nbsp;RdbPredicates):&nbsp;Promise | Deletes data from the RDB store based on the specified **RdbPredicates** object. This method uses a promise to return the result.<br>-&nbsp;**rdbPredicates**: conditions for deleting data. |
- **Querying data**
......@@ -66,12 +66,12 @@ The RDB provides APIs for inserting, deleting, updating, and querying data in th
**Table 5** APIs for querying data
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | query(rdbPredicates:&nbsp;RdbPredicates,&nbsp;columns:&nbsp;Array,&nbsp;callback:&nbsp;AsyncCallback&lt;ResultSet&gt;):&nbsp;void | Queries data in the RDB store based on the specified **RdbPredicates** object. This method uses a callback to return the result.<br>-&nbsp;**rdbPredicates**: conditions for querying data.<br>-&nbsp;**columns**: columns to query. If this parameter is not specified, the query applies to all columns.<br>-&nbsp;**callback**: callback invoked to return the result. If the operation is successful, a **ResultSet** object will be returned.|
| RdbStore | query(rdbPredicates:&nbsp;RdbPredicates,&nbsp;columns:&nbsp;Array):&nbsp;Promise&lt;ResultSet&gt; | Queries data in the RDB store based on the specified **RdbPredicates** object. This method uses a promise to return the result.<br>-&nbsp;**rdbPredicates**: conditions for querying data.<br>-&nbsp;**columns**: columns to query. If this parameter is not specified, the query applies to all columns.|
| RdbStore | querySql(sql:&nbsp;string,&nbsp;bindArgs:&nbsp;Array&lt;ValueType&gt;,&nbsp;callback:&nbsp;AsyncCallback&lt;ResultSet&gt;):void | Queries data in the RDB store using the specified SQL statement. This method uses a callback to return the result.<br>-&nbsp;**sql**: SQL statement.<br>-&nbsp;**bindArgs**: arguments in the SQL statement.<br>-&nbsp;**callback**: callback invoked to return the result. If the operation is successful, a **ResultSet** object will be returned.|
| RdbStore | querySql(sql:&nbsp;string,&nbsp;bindArgs?:&nbsp;Array&lt;ValueType&gt;):Promise&lt;ResultSet&gt; | Queries data in the RDB store using the specified SQL statement. This method uses a promise to return the result.<br>-&nbsp;**sql**: SQL statement.<br>-&nbsp;**bindArgs**: arguments in the SQL statement.|
| Class | API | Description |
| -------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
| RdbStore | query(rdbPredicates:&nbsp;RdbPredicates,&nbsp;columns:&nbsp;Array,&nbsp;callback:&nbsp;AsyncCallback&lt;ResultSet&gt;):&nbsp;void | Queries data in the RDB store based on the specified **RdbPredicates** object. This method uses a callback to return the result.<br>-&nbsp;**rdbPredicates**: conditions for querying data.<br>-&nbsp;**columns**: columns to query. If this parameter is not specified, the query applies to all columns.<br>-&nbsp;**callback**: callback invoked to return the result. If the operation is successful, a **ResultSet** object will be returned. |
| RdbStore | query(rdbPredicates:&nbsp;RdbPredicates,&nbsp;columns:&nbsp;Array):&nbsp;Promise&lt;ResultSet&gt; | Queries data in the RDB store based on the specified **RdbPredicates** object. This method uses a promise to return the result.<br>-&nbsp;**rdbPredicates**: conditions for querying data.<br>-&nbsp;**columns**: columns to query. If this parameter is not specified, the query applies to all columns. |
| RdbStore | querySql(sql:&nbsp;string,&nbsp;bindArgs:&nbsp;Array&lt;ValueType&gt;,&nbsp;callback:&nbsp;AsyncCallback&lt;ResultSet&gt;):void | Queries data in the RDB store using the specified SQL statement. This method uses a callback to return the result.<br>-&nbsp;**sql**: SQL statement.<br>-&nbsp;**bindArgs**: arguments in the SQL statement.<br>-&nbsp;**callback**: callback invoked to return the result. If the operation is successful, a **ResultSet** object will be returned. |
| RdbStore | querySql(sql:&nbsp;string,&nbsp;bindArgs?:&nbsp;Array&lt;ValueType&gt;):Promise&lt;ResultSet&gt; | Queries data in the RDB store using the specified SQL statement. This method uses a promise to return the result.<br>-&nbsp;**sql**: SQL statement.<br>-&nbsp;**bindArgs**: arguments in the SQL statement. |
### Using Predicates
......@@ -79,63 +79,63 @@ The RDB provides **RdbPredicates** for you to set database operation conditions.
**Table 6** APIs for using RDB store predicates
| Class| API| Description|
| -------- | -------- | -------- |
| RdbPredicates |inDevices(devices: Array<string>): RdbPredicates | Specifies remote devices on the network with RDB stores to be synchronized.<br>-&nbsp;**devices**: IDs of the remote devices on the network.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates |inAllDevices(): RdbPredicates | Connects to all remote devices on the network with RDB stores to be synchronized.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | equalTo(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value equal to the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | notEqualTo(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value not equal to the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | beginWrap():&nbsp;RdbPredicates | Adds a left parenthesis to the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** with a left parenthesis.|
| RdbPredicates | endWrap():&nbsp;RdbPredicates | Adds a right parenthesis to the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** with a right parenthesis.|
| RdbPredicates | or():&nbsp;RdbPredicates | Adds the OR condition to the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** with the OR condition.|
| RdbPredicates | and():&nbsp;RdbPredicates | Adds the AND condition to the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** with the AND condition.|
| RdbPredicates | contains(field:&nbsp;string,&nbsp;value:&nbsp;string):&nbsp;RdbPredicats | Sets the **RdbPredicates** to match a string containing the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified string.|
| RdbPredicates | beginsWith(field:&nbsp;string,&nbsp;value:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match a string that starts with the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | endsWith(field:&nbsp;string,&nbsp;value:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match a string that ends with the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | isNull(field:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field whose value is null.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | isNotNull(field:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field whose value is not null.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | like(field:&nbsp;string,&nbsp;value:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match a string that is similar to the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | glob(field:&nbsp;string,&nbsp;value:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the specified string.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | between(field:&nbsp;string,&nbsp;low:&nbsp;ValueType,&nbsp;high:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value within the specified range.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**low**: minimum value that matches the **RdbPredicates**.<br>-&nbsp;**high**: maximum value that matches the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | notBetween(field:&nbsp;string,&nbsp;low:&nbsp;ValueType,&nbsp;high:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value out of the specified range.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**low**: minimum value that matches the **RdbPredicates**.<br>-&nbsp;**high**: maximum value that matches the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | greaterThan(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicatesgr | Sets the **RdbPredicates** to match the field with data type **ValueType** and value greater than the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | lessThan(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value less than the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | greaterThanOrEqualTo(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value greater than or equal to the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | lessThanOrEqualTo(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value less than or equal to the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | orderByAsc(field:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the column with values sorted in ascending order.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | orderByDesc(field:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the column with values sorted in descending order.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | distinct():&nbsp;RdbPredicates | Sets the **RdbPredicates** to filter out duplicate records.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that can filter out duplicate records.|
| RdbPredicates | limitAs(value:&nbsp;number):&nbsp;RdbPredicates | Sets the **RdbPredicates** to specify the maximum number of records.<br>-&nbsp;**value**: maximum number of records.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that can be used to set the maximum number of records.|
| RdbPredicates | offsetAs(rowOffset:&nbsp;number):&nbsp;RdbPredicates | Sets the **RdbPredicates** to specify the start position of the returned result.<br>-&nbsp;**rowOffset**: start position of the returned result. The value is a positive integer.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that specifies the start position of the returned result.|
| RdbPredicates | groupBy(fields:&nbsp;Array&lt;string&gt;):&nbsp;RdbPredicates | Sets the **RdbPredicates** to group rows that have the same value into summary rows.<br>-&nbsp;**fields**: names of the columns grouped for querying data.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that groups rows with the same value.|
| RdbPredicates | indexedBy(indexName:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to specify the index column.<br>-&nbsp;**indexName**: name of the index column.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that specifies the index column.|
| RdbPredicates | in(field:&nbsp;string,&nbsp;value:&nbsp;Array&lt;ValueType&gt;):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **Array&#60;ValueType&#62;** and value within the specified range.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: array of **ValueType** to match.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | notIn(field:&nbsp;string,&nbsp;value:&nbsp;Array&lt;ValueType&gt;):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **Array&#60;ValueType&#62;** and value out of the specified range.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: array of **ValueType** to match.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| Class | API | Description |
| ------------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
| RdbPredicates | inDevices(devices: Array\<string>): RdbPredicates | Specifies remote devices on the network with RDB stores to be synchronized.<br>-&nbsp;**devices**: IDs of the remote devices on the network.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | inAllDevices(): RdbPredicates | Connects to all remote devices on the network with RDB stores to be synchronized.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | equalTo(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value equal to the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | notEqualTo(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value not equal to the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | beginWrap():&nbsp;RdbPredicates | Adds a left parenthesis to the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** with a left parenthesis. |
| RdbPredicates | endWrap():&nbsp;RdbPredicates | Adds a right parenthesis to the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** with a right parenthesis. |
| RdbPredicates | or():&nbsp;RdbPredicates | Adds the OR condition to the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** with the OR condition. |
| RdbPredicates | and():&nbsp;RdbPredicates | Adds the AND condition to the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** with the AND condition. |
| RdbPredicates | contains(field:&nbsp;string,&nbsp;value:&nbsp;string):&nbsp;RdbPredicats | Sets the **RdbPredicates** to match a string containing the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified string. |
| RdbPredicates | beginsWith(field:&nbsp;string,&nbsp;value:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match a string that starts with the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | endsWith(field:&nbsp;string,&nbsp;value:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match a string that ends with the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | isNull(field:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field whose value is null.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | isNotNull(field:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field whose value is not null.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | like(field:&nbsp;string,&nbsp;value:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match a string that is similar to the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | glob(field:&nbsp;string,&nbsp;value:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the specified string.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | between(field:&nbsp;string,&nbsp;low:&nbsp;ValueType,&nbsp;high:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value within the specified range.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**low**: minimum value that matches the **RdbPredicates**.<br>-&nbsp;**high**: maximum value that matches the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | notBetween(field:&nbsp;string,&nbsp;low:&nbsp;ValueType,&nbsp;high:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value out of the specified range.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**low**: minimum value that matches the **RdbPredicates**.<br>-&nbsp;**high**: maximum value that matches the **RdbPredicates**.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | greaterThan(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicatesgr | Sets the **RdbPredicates** to match the field with data type **ValueType** and value greater than the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | lessThan(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value less than the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | greaterThanOrEqualTo(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value greater than or equal to the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | lessThanOrEqualTo(field:&nbsp;string,&nbsp;value:&nbsp;ValueType):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **ValueType** and value less than or equal to the specified value.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: value specified.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | orderByAsc(field:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the column with values sorted in ascending order.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | orderByDesc(field:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the column with values sorted in descending order.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | distinct():&nbsp;RdbPredicates | Sets the **RdbPredicates** to filter out duplicate records.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that can filter out duplicate records. |
| RdbPredicates | limitAs(value:&nbsp;number):&nbsp;RdbPredicates | Sets the **RdbPredicates** to specify the maximum number of records.<br>-&nbsp;**value**: maximum number of records.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that can be used to set the maximum number of records. |
| RdbPredicates | offsetAs(rowOffset:&nbsp;number):&nbsp;RdbPredicates | Sets the **RdbPredicates** to specify the start position of the returned result.<br>-&nbsp;**rowOffset**: start position of the returned result. The value is a positive integer.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that specifies the start position of the returned result. |
| RdbPredicates | groupBy(fields:&nbsp;Array&lt;string&gt;):&nbsp;RdbPredicates | Sets the **RdbPredicates** to group rows that have the same value into summary rows.<br>-&nbsp;**fields**: names of the columns grouped for querying data.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that groups rows with the same value. |
| RdbPredicates | indexedBy(indexName:&nbsp;string):&nbsp;RdbPredicates | Sets the **RdbPredicates** to specify the index column.<br>-&nbsp;**indexName**: name of the index column.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that specifies the index column. |
| RdbPredicates | in(field:&nbsp;string,&nbsp;value:&nbsp;Array&lt;ValueType&gt;):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **Array&#60;ValueType&#62;** and value within the specified range.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: array of **ValueType** to match.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
| RdbPredicates | notIn(field:&nbsp;string,&nbsp;value:&nbsp;Array&lt;ValueType&gt;):&nbsp;RdbPredicates | Sets the **RdbPredicates** to match the field with data type **Array&#60;ValueType&#62;** and value out of the specified range.<br>-&nbsp;**field**: column name in the database table.<br>-&nbsp;**value**: array of **ValueType** to match.<br>-&nbsp;**RdbPredicates**: returns a **RdbPredicates** object that matches the specified field. |
### Using the Result Set
A result set can be regarded as a row of data in the queried results. It allows you to traverse and access the data you have queried. The following table describes the external APIs of **ResultSet**.
> ![icon-notice.gif](public_sys-resources/icon-notice.gif) **NOTICE**<br>
> **NOTICE**<br>
> After a result set is used, you must call the **close()** method to close it explicitly.
**Table 7** APIs for using the result set
| Class| API| Description|
| -------- | -------- | -------- |
| ResultSet | goTo(offset:number):&nbsp;boolean | Moves the result set forwards or backwards by the specified offset relative to its current position.|
| ResultSet | goToRow(position:&nbsp;number):&nbsp;boolean | Moves the result set to the specified row.|
| ResultSet | goToNextRow():&nbsp;boolean | Moves the result set to the next row.|
| ResultSet | goToPreviousRow():&nbsp;boolean | Moves the result set to the previous row.|
| ResultSet | getColumnIndex(columnName:&nbsp;string):&nbsp;number | Obtains the column index based on the specified column name.|
| ResultSet | getColumnName(columnIndex:&nbsp;number):&nbsp;string | Obtains the column name based on the specified column index.|
| ResultSet | goToFirstRow():&nbsp;boolean | Checks whether the result set is located in the first row.|
| ResultSet | goToLastRow():&nbsp;boolean | Checks whether the result set is located in the last row.|
| ResultSet | getString(columnIndex:&nbsp;number):&nbsp;string | Obtains the value in the specified column of the current row, in a string.|
| ResultSet | getBlob(columnIndex:&nbsp;number):&nbsp;Uint8Array | Obtains the values in the specified column of the current row, in a byte array.|
| ResultSet | getDouble(columnIndex:&nbsp;number):&nbsp;number | Obtains the values in the specified column of the current row, in double.|
| ResultSet | isColumnNull(columnIndex:&nbsp;number):&nbsp;boolean | Checks whether the value in the specified column of the current row is null.|
| ResultSet | close():&nbsp;void | Closes the result set.|
| Class | API | Description |
| --------- | ---------------------------------------------------- | ------------------------------------------------------------ |
| ResultSet | goTo(offset:number):&nbsp;boolean | Moves the result set forwards or backwards by the specified offset relative to its current position. |
| ResultSet | goToRow(position:&nbsp;number):&nbsp;boolean | Moves the result set to the specified row. |
| ResultSet | goToNextRow():&nbsp;boolean | Moves the result set to the next row. |
| ResultSet | goToPreviousRow():&nbsp;boolean | Moves the result set to the previous row. |
| ResultSet | getColumnIndex(columnName:&nbsp;string):&nbsp;number | Obtains the column index based on the specified column name. |
| ResultSet | getColumnName(columnIndex:&nbsp;number):&nbsp;string | Obtains the column name based on the specified column index. |
| ResultSet | goToFirstRow():&nbsp;boolean | Checks whether the result set is located in the first row. |
| ResultSet | goToLastRow():&nbsp;boolean | Checks whether the result set is located in the last row. |
| ResultSet | getString(columnIndex:&nbsp;number):&nbsp;string | Obtains the value in the specified column of the current row, in a string. |
| ResultSet | getBlob(columnIndex:&nbsp;number):&nbsp;Uint8Array | Obtains the values in the specified column of the current row, in a byte array. |
| ResultSet | getDouble(columnIndex:&nbsp;number):&nbsp;number | Obtains the values in the specified column of the current row, in double. |
| ResultSet | isColumnNull(columnIndex:&nbsp;number):&nbsp;boolean | Checks whether the value in the specified column of the current row is null. |
| ResultSet | close():&nbsp;void | Closes the result set. |
......@@ -145,10 +145,10 @@ A result set can be regarded as a row of data in the queried results. It allows
**Table 8** APIs for setting distributed tables
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | setDistributedTables(tables: Array<string>, callback: AsyncCallback<void>): void;| Sets a list of distributed tables. This method uses a callback to return the result.<br>- &nbsp;**tables**: names of the distributed tables to set.<br>-&nbsp;**callback**: callback invoked to return the result.|
| RdbStore | setDistributedTables(tables: Array<string>): Promise<void>; | Sets a list of distributed tables. This method uses a promise to return the result.<br>- &nbsp;**tables**: names of the distributed tables to set.|
| Class | API | Description |
| -------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
| RdbStore | setDistributedTables(tables: Array\<string>, callback: AsyncCallback\<void>): void | Sets a list of distributed tables. This method uses a callback to return the result.<br>- &nbsp;**tables**: names of the distributed tables to set.<br>-&nbsp;**callback**: callback invoked to return the result. |
| RdbStore | setDistributedTables(tables: Array\<string>): Promise\<void> | Sets a list of distributed tables. This method uses a promise to return the result.<br>- &nbsp;**tables**: names of the distributed tables to set. |
**Obtaining the Distributed Table Name for a Remote Device**
......@@ -156,35 +156,35 @@ You can obtain the distributed table name for a remote device based on the local
**Table 9** APIs for obtaining the distributed table name of a remote device
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | obtainDistributedTableName(device: string, table: string, callback: AsyncCallback<string>): void; | Obtains the distributed table name for a remote device based on the local table name. The distributed table name is used to query the RDB store of the remote device. This method uses a callback to return the result.<br>-&nbsp;**device**: remote device.<br>- &nbsp;**table**: local table name.<br>- &nbsp;**callback**: callback used to return the result. If the operation is successful, the distributed table name of the remote device will be returned. |
| RdbStore | obtainDistributedTableName(device: string, table: string): Promise<string>; | Obtains the distributed table name for a remote device based on the local table name. The distributed table name is used to query the RDB store of the remote device. This method uses a promise to return the result.<br>-&nbsp;**device**: remote device.<br>- &nbsp;**table**: local table name.|
| Class | API | Description |
| -------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
| RdbStore | obtainDistributedTableName(device: string, table: string, callback: AsyncCallback\<string>): void | Obtains the distributed table name for a remote device based on the local table name. The distributed table name is used to query the RDB store of the remote device. This method uses a callback to return the result.<br>-&nbsp;**device**: remote device.<br>- &nbsp;**table**: local table name.<br>- &nbsp;**callback**: callback used to return the result. If the operation is successful, the distributed table name of the remote device will be returned. |
| RdbStore | obtainDistributedTableName(device: string, table: string): Promise\<string> | Obtains the distributed table name for a remote device based on the local table name. The distributed table name is used to query the RDB store of the remote device. This method uses a promise to return the result.<br>-&nbsp;**device**: remote device.<br>- &nbsp;**table**: local table name. |
**Synchronizing Data Between Devices**
**Table 10** APIs for synchronizing data between devices
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | sync(mode: SyncMode, predicates: RdbPredicates, callback: AsyncCallback<Array<[string, number]>>): void;| Synchronizes data between devices. This method uses a callback to return the result.<br>-&nbsp;**mode**: data synchronization mode. **SYNC\_MODE\_PUSH** means to push data from the local device to a remote device. **SYNC\_MODE\_PULL** means to pull data from a remote device to the local device.<br>-&nbsp;**predicates**: data and devices to be synchronized.<br>-&nbsp;**callback**: callback invoked to return the result. In the result, **string** indicates the device ID, and **number** indicates the synchronization status of each device. The value **0** indicates a success, and other values indicate a failure.|
| RdbStore | sync(mode: SyncMode, predicates: RdbPredicates): Promise<Array<[string, number]>>;| Synchronizes data between devices. This method uses a promise to return the result.<br>-&nbsp;**mode**: data synchronization mode. **SYNC\_MODE\_PUSH** means to push data from the local device to a remote device. **SYNC\_MODE\_PULL** means to pull data from a remote device to the local device.<br>-&nbsp;**predicates**: data and devices to be synchronized. |
| Class | API | Description |
| -------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
| RdbStore | sync(mode: SyncMode, predicates: RdbPredicates, callback: AsyncCallback<Array<[string, number]>>): void | Synchronizes data between devices. This method uses a callback to return the result.<br>-&nbsp;**mode**: data synchronization mode. **SYNC\_MODE\_PUSH** means to push data from the local device to a remote device. **SYNC\_MODE\_PULL** means to pull data from a remote device to the local device.<br>-&nbsp;**predicates**: data and devices to be synchronized.<br>-&nbsp;**callback**: callback invoked to return the result. In the result, **string** indicates the device ID, and **number** indicates the synchronization status of each device. The value **0** indicates a success, and other values indicate a failure. |
| RdbStore | sync(mode: SyncMode, predicates: RdbPredicates): Promise<Array<[string, number]>> | Synchronizes data between devices. This method uses a promise to return the result.<br>-&nbsp;**mode**: data synchronization mode. **SYNC\_MODE\_PUSH** means to push data from the local device to a remote device. **SYNC\_MODE\_PULL** means to pull data from a remote device to the local device.<br>-&nbsp;**predicates**: data and devices to be synchronized. |
**Registering an RDB Store Observer**
**Table 11** API for registering an observer
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore |on(event: 'dataChange', type: SubscribeType, observer: Callback<Array<string>>): void;| Registers an observer for this RDB store to subscribe to distributed data changes. When data in the RDB store changes, a callback will be invoked to return the data changes.<br>-&nbsp;**type**: subscription type. **SUBSCRIBE\_TYPE\_REMOTE** means to subscribe to remote data changes.<br>-&nbsp;**observer**: observer that listens for data changes in the RDB store.|
| Class | API | Description |
| -------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
| RdbStore | on(event: 'dataChange', type: SubscribeType, observer: Callback<Array\<string>>): void | Registers an observer for this RDB store to subscribe to distributed data changes. When data in the RDB store changes, a callback will be invoked to return the data changes.<br>-&nbsp;**type**: subscription type. **SUBSCRIBE\_TYPE\_REMOTE** means to subscribe to remote data changes.<br>-&nbsp;**observer**: observer that listens for data changes in the RDB store. |
**Unregistering an RDB Store Observer**
**Table 12** API for unregistering an observer
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore |off(event:'dataChange', type: SubscribeType, observer: Callback<Array<string>>): void;| Unregisters the observer of the specified type for the RDB store. This method uses a callback to return the result.<br>- &nbsp;**type**: subscription type. **SUBSCRIBE\_TYPE\_REMOTE** means to subscribe to remote data changes.<br>- &nbsp;**observer**: observer to unregister.|
| Class | API | Description |
| -------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
| RdbStore | off(event:'dataChange', type: SubscribeType, observer: Callback<Array\<string>>): void | Unregisters the observer of the specified type for the RDB store. This method uses a callback to return the result.<br>- &nbsp;**type**: subscription type. **SUBSCRIBE\_TYPE\_REMOTE** means to subscribe to remote data changes.<br>- &nbsp;**observer**: observer to unregister. |
## How to Develop
......@@ -305,9 +305,4 @@ You can obtain the distributed table name for a remote device based on the local
```js
let tableName = rdbStore.obtainDistributedTableName(deviceId, "test");
let resultSet = rdbStore.querySql("SELECT * FROM " + tableName)
```
## Samples
The following samples are provided for you to better understand the RDB development:
- [`Rdb`: eTS RDB (API8)](https://gitee.com/openharmony/app_samples/tree/master/data/Rdb)
- [`DistributedRdb`: eTS Distributed Relational Database (API8)](https://gitee.com/openharmony/app_samples/tree/master/data/DistributedRdb)
- [Relational Database](https://gitee.com/openharmony/codelabs/tree/master/Data/JSRelationshipData)
```
\ No newline at end of file
Markdown is supported
0% 或 .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑！
想要评论请 注册 或