@@ -15,7 +15,7 @@ Call **createDistributedObject()** to create a distributed data object instance.
**Table 1** API for creating a distributed data object instance
| Package| API| Description|
| -------- | -------- | -------- |
| ohos.data.distributedDataObject| createDistributedObject(source: object): DistributedObject | Creates a distributed data object instance for data operations.|
| ohos.data.distributedDataObject| createDistributedObject(source: object): DistributedObject | Creates a distributed data object instance for data operations.<br>- **source**: attributes of the **distributedObject** set.<br>- **DistributedObject**: returns the distributed object created.|
### Generating a Session ID
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@@ -43,7 +43,7 @@ Call **on()** to subscribe to data changes of a distributed data object. When th
| Class| API| Description|
| -------- | -------- | -------- |
| DistributedDataObject| on(type: 'change', callback: Callback<{sessionId:string,fields:Array<string>}>): void | Subscribes to data changes.|
| DistributedDataObject| off(type: 'change', callback?: Callback<{sessionId:string,fields:Array<string>}>): void | Unsubscribes from data changes.|
| DistributedDataObject| off(type: 'change', callback?: Callback<{sessionId:string,fields:Array<string>}>): void | Unsubscribes from data changes. Callback used to return changes of the distributed object. If this parameter is not specified, all callbacks related to data changes will be unregistered.|
### Observing Online or Offline Status
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@@ -82,13 +82,13 @@ The following example shows how to implement a distributed data object synchroni
// After obtaining that the device status goes online, the remote object synchronizes data. That is, name changes to jack and age to 18.
```
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@@ -97,7 +97,7 @@ The following example shows how to implement a distributed data object synchroni
The sample code is as follows:
```js
changeCallback:function(sessionId,changeData){
functionchangeCallback(sessionId,changeData){
console.info("change"+sessionId);
if(changeData!=null&&changeData!=undefined){
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@@ -147,7 +147,7 @@ The following example shows how to implement a distributed data object synchroni
8. Subscribe to the status (online/offline) changes of the distributed data object. A callback will be invoked to report the status change when the target distributed data object goes online or offline.
@@ -162,7 +162,7 @@ The following example shows how to implement a distributed data object synchroni
// unsubscribe from all status change callbacks.
local_object.off("status");
```
10. Remove the distributed data object from the synchronization network. After the distributed data object is removed from the network, the data changes on the local end will not be synchronized to the remote end.
10. Remove a distributed data object from the synchronization network. After the distributed data object is removed from the network, the data changes on the local end will not be synchronized to the remote end.
@@ -7,7 +7,7 @@ On the basis of the SQLite database, the relational database (RDB) allows you to
## Available APIs
**Creating and Deleting an RDB Store**
### Creating or Deleting an RDB Store
The following table describes the APIs available for creating and deleting an RDB store.
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@@ -17,51 +17,55 @@ The following table describes the APIs available for creating and deleting an RD
| -------- | -------- |
|getRdbStore(config: StoreConfig, version: number, callback: AsyncCallback<RdbStore>): 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>- **config**: configuration of the RDB store.<br>- **version**: RDB version.<br>- **callback**: callback invoked to return the RDB store obtained.|
|getRdbStore(config: StoreConfig, version: number): Promise<RdbStore> | 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>- **config**: configuration of the RDB store.<br>- **version**: RDB version.|
|deleteRdbStore(name: string, callback: AsyncCallback<void>): void | Deletes an RDB store. This method uses a callback to return the result. <br>- **name**: RDB store to delete.<br>- **callback**: callback invoked to return the result. If the RDB store is deleted, **true** will be returned. Otherwise, **false** will be returned.|
|deleteRdbStore(name: string, callback: AsyncCallback<void>): void | Deletes an RDB store. This method uses a callback to return the result. <br>- **name**: RDB store to delete.<br>- **callback**: callback invoked to return the result.|
| deleteRdbStore(name: string): Promise<void> | Deletes an RDB store. This method uses a promise to return the result.<br>- **name**: RDB store to delete.|
**Managing Data in an RDB Store**
### Managing Data in an RDB Store
The RDB provides APIs for inserting, deleting, updating, and querying data in the local RDB store.
-**Inserting data**<br/>
-**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.
**Table 2** APIs for inserting data
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | insert(name: string, values: ValuesBucket, callback: AsyncCallback<number>):void | Inserts a row of data into a table. This method uses a callback to return the result.<br>- **name**: name of the target table.<br>- **values**: data to be inserted into the table.<br>- **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: string, values: ValuesBucket): Promise<number> | Inserts a row of data into a table. This method uses a promise to return the result.<br>- **name**: name of the target table.<br>- **values**: data to be inserted into the table.|
-**Updating data**<br/>
-**Updating data**
Call the **update()** method to pass new data and specify the update conditions by using **RdbPredicates**. If the data is updated, the number of rows of the updated data will be returned; otherwise, **0** will be returned.
**Table 3** APIs for updating data
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | update(values: ValuesBucket, rdbPredicates: RdbPredicates, callback: AsyncCallback<number>):void | Updates data in the RDB store based on the specified **RdbPredicates** object. This method uses a callback to return the result.<br>- **values**: data to update, which is stored in a **ValuesBucket**.<br>- **rdbPredicates**: conditions for updating data.<br>- **callback**: callback invoked to return the number of rows updated.|
| RdbStore | update(values: ValuesBucket, rdbPredicates: RdbPredicates): Promise | Updates data in the RDB store based on the specified **RdbPredicates** object. This method uses a promise to return the result.<br>- **values**: data to update, which is stored in a **ValuesBucket**.<br>- **rdbPredicates**: conditions for updating data.|
-**Deleting data**<br/>
-**Deleting data**
Call the **delete()** method to delete data meeting the conditions specified by **RdbPredicates**. If the data is deleted, the number of rows of the deleted data will be returned; otherwise, **0** will be returned.
**Table 4** APIs for deleting data
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | delete(rdbPredicates: RdbPredicates, callback: AsyncCallback<number>):void | Deletes data from the RDB store based on the specified **RdbPredicates** object. This method uses a callback to return the result.<br>- **rdbPredicates**: conditions for deleting data.<br>- **callback**: callback invoked to return the number of rows deleted.|
| RdbStore | delete(rdbPredicates: RdbPredicates): Promise | Deletes data from the RDB store based on the specified **RdbPredicates** object. This method uses a promise to return the result.<br>- **rdbPredicates**: conditions for deleting data.|
-**Querying data**
-**Querying data**<br/>
You can query data in an RDB store in either of the following ways:
- Call the **query()** method to query data based on the predicates, without passing any SQL statement.
- Run the native SQL statement.
**Table 5** APIs for querying data
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | query(rdbPredicates: RdbPredicates, columns: Array, callback: AsyncCallback<ResultSet>): void | Queries data in the RDB store based on the specified **RdbPredicates** object. This method uses a callback to return the result.<br>- **rdbPredicates**: conditions for querying data.<br>- **columns**: columns to query. If this parameter is not specified, the query applies to all columns.<br>- **callback**: callback invoked to return the result. If the operation is successful, a **ResultSet** object will be returned.|
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@@ -69,7 +73,7 @@ The RDB provides APIs for inserting, deleting, updating, and querying data in th
| RdbStore | querySql(sql: string, bindArgs: Array<ValueType>, callback: AsyncCallback<ResultSet>):void | Queries data in the RDB store using the specified SQL statement. This method uses a callback to return the result.<br>- **sql**: SQL statement.<br>- **bindArgs**: arguments in the SQL statement.<br>- **callback**: callback invoked to return the result. If the operation is successful, a **ResultSet** object will be returned.|
| RdbStore | querySql(sql: string, bindArgs?: Array<ValueType>):Promise<ResultSet> | Queries data in the RDB store using the specified SQL statement. This method uses a promise to return the result.<br>- **sql**: SQL statement.<br>- **bindArgs**: arguments in the SQL statement.|
**Using Predicates**
### Using Predicates
The RDB provides **RdbPredicates** for you to set database operation conditions.
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@@ -108,12 +112,12 @@ The RDB provides **RdbPredicates** for you to set database operation conditions.
| RdbPredicates | in(field: string, value: Array<ValueType>): RdbPredicates | Sets the **RdbPredicates** to match the field with data type **Array<ValueType>** and value within the specified range.<br>- **field**: column name in the database table.<br>- **value**: array of **ValueType** to match.<br>- **RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
| RdbPredicates | notIn(field: string, value: Array<ValueType>): RdbPredicates | Sets the **RdbPredicates** to match the field with data type **Array<ValueType>** and value out of the specified range.<br>- **field**: column name in the database table.<br>- **value**: array of **ValueType** to match.<br>- **RdbPredicates**: returns a **RdbPredicates** object that matches the specified field.|
**Using the Result Set**
### 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**.
> After a result set is used, you must call the **close()** method to close it explicitly.
> After a result set is used, you must call the **close()** method to close it explicitly.**
**Table 7** APIs for using the result set
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@@ -133,26 +137,13 @@ A result set can be regarded as a row of data in the queried results. It allows
| ResultSet | isColumnNull(columnIndex: number): boolean | Checks whether the value in the specified column of the current row is null.|
| ResultSet | close(): void | Closes the result set.|
**Changing the Encryption Key for an RDB Store**
You can encrypt an RDB store.
When creating an RDB store, you can add a key for security purposes. After that, the RDB store can be accessed only with the correct key. You can change the key but cannot delete it.
Once an RDB store is created without a key, you can no longer add a key for it.
**Table 8** APIs for changing the encryption key
| Class| API| Description|
| -------- | -------- | -------- |
| RdbStore | changeEncryptKey(newEncryptKey:Uint8Array, callback: AsyncCallback<number>):void; | Changes the encryption key for this RDB store. This method uses a callback to return the result. If the operation is successful, **0** will be returned. Otherwise, a non-zero value will be returned.|
| RdbStore | changeEncryptKey(newEncryptKey:Uint8Array): Promise<number>; | Changes the encryption key for this RDB store. This method uses a promise to return the result. If the operation is successful, **0** will be returned. Otherwise, a non-zero value will be returned.|
### Setting Distributed Tables
**Setting Distributed Tables**
You can set a list of distributed tables for data operations across devices.
**Table 9** APIs for setting distributed tables
**Table 8** APIs for setting distributed tables
| Class| API| Description|
| -------- | -------- | -------- |
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@@ -163,7 +154,7 @@ You can set a list of distributed tables for data operations across devices.
You can obtain the distributed table name for a remote device based on the local table name. The distributed table name can be used to query the RDB store of the remote device.
**Table 10** API for obtaining the distributed table name of a remote device
**Table 9** APIs for obtaining the distributed table name of a remote device
| Class| API| Description|
| -------- | -------- | -------- |
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@@ -172,17 +163,16 @@ You can obtain the distributed table name for a remote device based on the local
**Synchronizing Data Between Devices**
**Table 11** APIs for 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>- **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>- **predicates**: data and devices to be synchronized.<br>- **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>- **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>- **predicates**: data and devices to be synchronized. |
**Registering an RDB Store Observer**
**Table 12** API for registering an observer
**Table 11** API for registering an observer
| Class| API| Description|
| -------- | -------- | -------- |
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@@ -190,7 +180,7 @@ You can obtain the distributed table name for a remote device based on the local
**Unregistering an RDB Store Observer**
**Table 13** API for unregistering an observer
**Table 12** API for unregistering an observer
| Class| API| Description|
| -------- | -------- | -------- |
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@@ -211,9 +201,10 @@ You can obtain the distributed table name for a remote device based on the local
const CREATE_TABLE_TEST = "CREATE TABLE IF NOT EXISTS test (" + "id INTEGER PRIMARY KEY AUTOINCREMENT, " + "name TEXT NOT NULL, " + "age INTEGER, " + "salary REAL, " + "blobType BLOB)";
const STORE_CONFIG = {name: "rdbstore.db",}
let rdbStore = await data_rdb.getRdbStore(STORE_CONFIG, 1);
await rdbStore.executeSql(CREATE_TABLE_TEST);
data_rdb.getRdbStore(STORE_CONFIG, 1, function (err, rdbStore) {
rdbStore.executeSql(SQL_CREATE_TABLE)
console.info('create table done.')
})
```
2. Insert data.
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@@ -238,16 +229,16 @@ You can obtain the distributed table name for a remote device based on the local
```
let predicates = new data_rdb.RdbPredicates("test");
predicates.equalTo("name", "Tom")
let resultSet = await rdbStore.query(predicates)
resultSet.goToFirstRow()
const id = await resultSet.getLong(resultSet.getColumnIndex("id"))
const name = await resultSet.getString(resultSet.getColumnIndex("name"))
const age = await resultSet.getLong(resultSet.getColumnIndex("age"))
