@ohos.data.rdb (RDB)

The relational database (RDB) manages data based on relational models. With the underlying SQLite database, the RDB provides a complete mechanism for managing local databases. To satisfy different needs in complicated scenarios, the RDB offers a series of methods for performing operations such as adding, deleting, modifying, and querying data, and supports direct execution of SQL statements. The worker threads are not supported.

This module provides the following RDB-related functions:

• RdbPredicates: provides predicates indicating the nature, feature, or relationship of a data entity in an RDB store. It is used to define the operation conditions for an RDB store.
• RdbStore: provides APIs for managing an RDB store.

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.

The APIs of this module are no longer maintained since API version 9. You are advised to use @ohos.data.relationalStore.

Modules to Import

import data_rdb from '@ohos.data.rdb';

data_rdb.getRdbStore

getRdbStore(context: Context, config: StoreConfig, version: number, callback: AsyncCallback<RdbStore>): void

Obtains an RDB store. This API uses an asynchronous callback to return the result. You can set parameters for the RDB store based on service requirements and call APIs to perform data operations.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

FA model:

// Obtain the context.
import featureAbility from '@ohos.ability.featureAbility'
let context = featureAbility.getContext()

// Call getRdbStore.
const STORE_CONFIG = { name: "RdbTest.db"}
data_rdb.getRdbStore(context, STORE_CONFIG, 1, function (err, rdbStore) {
    if (err) {
        console.info("Failed to get RdbStore, err: " + err)
        return
    }
    console.log("Got RdbStore successfully.")
})

Stage model:

// Obtain the context.
import UIAbility from '@ohos.app.ability.UIAbility';

let context;
class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage){
        context = this.context
    }
}

// Call getRdbStore.
const STORE_CONFIG = { name: "RdbTest.db"}
data_rdb.getRdbStore(context, STORE_CONFIG, 1, function (err, rdbStore) {
    if (err) {
        console.info("Failed to get RdbStore, err: " + err)
        return
    }
    console.log("Got RdbStore successfully.")
})

data_rdb.getRdbStore

getRdbStore(context: Context, config: StoreConfig, version: number): Promise<RdbStore>

Obtains an RDB store. This API uses a promise to return the result. You can set parameters for the RDB store based on service requirements and call APIs to perform data operations.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

FA model:

// Obtain the context.
import featureAbility from '@ohos.ability.featureAbility'
let context = featureAbility.getContext()

// Call getRdbStore.
const STORE_CONFIG = { name: "RdbTest.db" }
let promise = data_rdb.getRdbStore(context, STORE_CONFIG, 1);
promise.then(async (rdbStore) => {
    console.log("Got RdbStore successfully.")
}).catch((err) => {
    console.log("Failed to get RdbStore, err: " + err)
})

Stage model:

// Obtain the context.
import UIAbility from '@ohos.app.ability.UIAbility';

let context;
class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage){
        context = this.context
    }
}

// Call getRdbStore.
const STORE_CONFIG = { name: "RdbTest.db" }
let promise = data_rdb.getRdbStore(context, STORE_CONFIG, 1);
promise.then(async (rdbStore) => {
    console.log("Got RdbStore successfully.")
}).catch((err) => {
    console.log("Failed to get RdbStore, err: " + err)
})

data_rdb.deleteRdbStore

deleteRdbStore(context: Context, name: string, callback: AsyncCallback<void>): void

Deletes an RDB store. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

FA model:

// Obtain the context.
import featureAbility from '@ohos.ability.featureAbility'
let context = featureAbility.getContext()

// Call deleteRdbStore.
data_rdb.deleteRdbStore(context, "RdbTest.db", function (err) {
    if (err) {
        console.info("Failed to delete RdbStore, err: " + err)
        return
    }
    console.log("Deleted RdbStore successfully.")
})

Stage model:

// Obtain the context.
import UIAbility from '@ohos.app.ability.UIAbility';

let context;
class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage){
        context = this.context
    }
}

// Call deleteRdbStore.
data_rdb.deleteRdbStore(context, "RdbTest.db", function (err) {
    if (err) {
        console.info("Failed to delete RdbStore, err: " + err)
        return
    }
    console.log("Deleted RdbStore successfully.")
})

data_rdb.deleteRdbStore

deleteRdbStore(context: Context, name: string): Promise<void>

Deletes an RDB store. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

FA model:

// Obtain the context.
import featureAbility from '@ohos.ability.featureAbility'
let context = featureAbility.getContext()

// Call deleteRdbStore.
let promise = data_rdb.deleteRdbStore(context, "RdbTest.db")
promise.then(() => {
    console.log("Deleted RdbStore successfully.")
}).catch((err) => {
    console.info("Failed to delete RdbStore, err: " + err)
})

Stage model:

// Obtain the context.
import UIAbility from '@ohos.app.ability.UIAbility';

let context;
class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage){
        context = this.context
    }
}

// Call deleteRdbStore.
let promise = data_rdb.deleteRdbStore(context, "RdbTest.db")
promise.then(()=>{
    console.log("Deleted RdbStore successfully.")
}).catch((err) => {
    console.info("Failed to delete RdbStore, err: " + err)
})

ValueType

Defines the data types allowed.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

ValuesBucket

Defines the types of the key and value in a KV pair.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

SyncMode⁸⁺

Defines the database synchronization mode.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

SubscribeType⁸⁺

Defines the subscription type.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

StoreConfig

Defines the RDB store configuration.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

RdbPredicates

Defines predicates for an RDB store. This class determines whether the conditional expression for the RDB store is true or false.

constructor

constructor(name: string)

A constructor used to create an RdbPredicates object.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")

inDevices⁸⁺

inDevices(devices: Array<string>): RdbPredicates

Sets an RdbPredicates to specify the remote devices to connect on the network during distributed database synchronization.

NOTE

The value of devices is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

import deviceManager from '@ohos.distributedHardware.deviceManager';
let dmInstance = null;
let deviceIds = [];

deviceManager.createDeviceManager("com.example.appdatamgrverify", (err, manager) => {
    if (err) {
        console.log("create device manager failed, err=" + err);
        return;
    }
    dmInstance = manager;
    let devices = dmInstance.getTrustedDeviceListSync();
    for (var i = 0; i < devices.length; i++) {
        deviceIds[i] = devices[i].deviceId;
    }
})
                                  
let predicates = new data_rdb.RdbPredicates("EMPLOYEE");
predicates.inDevices(deviceIds);

inAllDevices⁸⁺

inAllDevices(): RdbPredicates

Sets an RdbPredicates to specify all remote devices on the network to connect during distributed database synchronization.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.inAllDevices()

equalTo

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

Sets an RdbPredicates to match the field with data type ValueType and value equal to the specified value.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "lisi")

notEqualTo

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.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.notEqualTo("NAME", "lisi")

beginWrap

beginWrap(): RdbPredicates

Adds a left parenthesis to the RdbPredicates.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "lisi")
    .beginWrap()
    .equalTo("AGE", 18)
    .or()
    .equalTo("SALARY", 200.5)
    .endWrap()

endWrap

endWrap(): RdbPredicates

Adds a right parenthesis to the RdbPredicates.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "lisi")
    .beginWrap()
    .equalTo("AGE", 18)
    .or()
    .equalTo("SALARY", 200.5)
    .endWrap()

or

or(): RdbPredicates

Adds the OR condition to the RdbPredicates.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Lisa")
    .or()
    .equalTo("NAME", "Rose")

and

and(): RdbPredicates

Adds the AND condition to the RdbPredicates.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Lisa")
    .and()
    .equalTo("SALARY", 200.5)

contains

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

Sets an RdbPredicates to match a string containing the specified value.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.contains("NAME", "os")

beginsWith

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

Sets an RdbPredicates to match a string that starts with the specified value.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.beginsWith("NAME", "os")

endsWith

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

Sets an RdbPredicates to match a string that ends with the specified value.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.endsWith("NAME", "se")

isNull

isNull(field: string): RdbPredicates

Sets an RdbPredicates to match the field whose value is null.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.isNull("NAME")

isNotNull

isNotNull(field: string): RdbPredicates

Sets an RdbPredicates to match the field whose value is not null.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.isNotNull("NAME")

like

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

Sets an RdbPredicates to match a string that is similar to the specified value.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.like("NAME", "%os%")

glob

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

Sets an RdbPredicates to match the specified string.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.glob("NAME", "?h*g")

between

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

Sets an RdbPredicates to match the field with data type ValueType and value within the specified range.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.between("AGE", 10, 50)

notBetween

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

Sets an RdbPredicates to match the field with data type ValueType and value out of the specified range.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.notBetween("AGE", 10, 50)

greaterThan

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

Sets an RdbPredicates to match the field with data type ValueType and value greater than the specified value.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.greaterThan("AGE", 18)

lessThan

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

Sets an RdbPredicates to match the field with data type ValueType and value less than the specified value.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.lessThan("AGE", 20)

greaterThanOrEqualTo

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

Sets an RdbPredicates to match the field with data type ValueType and value greater than or equal to the specified value.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.greaterThanOrEqualTo("AGE", 18)

lessThanOrEqualTo

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

Sets an RdbPredicates to match the field with data type ValueType and value less than or equal to the specified value.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.lessThanOrEqualTo("AGE", 20)

orderByAsc

orderByAsc(field: string): RdbPredicates

Sets an RdbPredicates to match the column with values sorted in ascending order.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.orderByAsc("NAME")

orderByDesc

orderByDesc(field: string): RdbPredicates

Sets an RdbPredicates to match the column with values sorted in descending order.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.orderByDesc("AGE")

distinct

distinct(): RdbPredicates

Sets an RdbPredicates to filter out duplicate records.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Rose").distinct()

limitAs

limitAs(value: number): RdbPredicates

Sets an RdbPredicates to specify the maximum number of records.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Rose").limitAs(3)

offsetAs

offsetAs(rowOffset: number): RdbPredicates

Sets an RdbPredicates to specify the start position of the returned result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Rose").offsetAs(3)

groupBy

groupBy(fields: Array<string>): RdbPredicates

Sets an RdbPredicates to group rows that have the same value into summary rows.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.groupBy(["AGE", "NAME"])

indexedBy

indexedBy(field: string): RdbPredicates

Sets an RdbPredicates object to specify the index column.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.indexedBy("SALARY_INDEX")

in

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

Sets an RdbPredicates to match the field with data type Array<ValueType> and value within the specified range.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.in("AGE", [18, 20])

notIn

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

Sets an RdbPredicates to match the field with data type Array<ValueType> and value out of the specified range.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.notIn("NAME", ["Lisa", "Rose"])

RdbStore

Provides methods to manage an RDB store.

Before using the APIs of this class, use executeSql to initialize the database table structure and related data.

insert

insert(table: string, values: ValuesBucket, callback: AsyncCallback<number>):void

Inserts a row of data into a table. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

const valueBucket = {
    "NAME": "Lisa",
    "AGE": 18,
    "SALARY": 100.5,
    "CODES": new Uint8Array([1, 2, 3, 4, 5]),
}
rdbStore.insert("EMPLOYEE", valueBucket, function (status, rowId) {
    if (status) {
        console.log("Failed to insert data");
        return;
    }
    console.log("Inserted data successfully, rowId = " + rowId);
})

insert

insert(table: string, values: ValuesBucket):Promise<number>

Inserts a row of data into a table. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

const valueBucket = {
    "NAME": "Lisa",
    "AGE": 18,
    "SALARY": 100.5,
    "CODES": new Uint8Array([1, 2, 3, 4, 5]),
}
let promise = rdbStore.insert("EMPLOYEE", valueBucket)
promise.then((rowId) => {
    console.log("Inserted data successfully, rowId = " + rowId);
}).catch((status) => {
    console.log("Failed to insert data");
})

batchInsert

batchInsert(table: string, values: Array<ValuesBucket>, callback: AsyncCallback<number>):void

Batch inserts data into a table. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

const valueBucket1 = {
    "NAME": "Lisa",
    "AGE": 18,
    "SALARY": 100.5,
    "CODES": new Uint8Array([1, 2, 3, 4, 5])
}
const valueBucket2 = {
    "NAME": "Jack",
    "AGE": 19,
    "SALARY": 101.5,
    "CODES": new Uint8Array([6, 7, 8, 9, 10])
}
const valueBucket3 = {
    "NAME": "Tom",
    "AGE": 20,
    "SALARY": 102.5,
    "CODES": new Uint8Array([11, 12, 13, 14, 15])
}

let valueBuckets = new Array(valueBucket1, valueBucket2, valueBucket3);
rdbStore.batchInsert("EMPLOYEE", valueBuckets, function(status, insertNum) {
    if (status) {
        console.log("batchInsert is failed, status = " + status);
        return;
    }
    console.log("batchInsert is successful, the number of values that were inserted = " + insertNum);
})

batchInsert

batchInsert(table: string, values: Array<ValuesBucket>):Promise<number>

Batch inserts data into a table. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

const valueBucket1 = {
    "NAME": "Lisa",
    "AGE": 18,
    "SALARY": 100.5,
    "CODES": new Uint8Array([1, 2, 3, 4, 5])
}
const valueBucket2 = {
    "NAME": "Jack",
    "AGE": 19,
    "SALARY": 101.5,
    "CODES": new Uint8Array([6, 7, 8, 9, 10])
}
const valueBucket3 = {
    "NAME": "Tom",
    "AGE": 20,
    "SALARY": 102.5,
    "CODES": new Uint8Array([11, 12, 13, 14, 15])
}

let valueBuckets = new Array(valueBucket1, valueBucket2, valueBucket3);
let promise = rdbStore.batchInsert("EMPLOYEE", valueBuckets);
promise.then((insertNum) => {
    console.log("batchInsert is successful, the number of values that were inserted = " + insertNum);
}).catch((status) => {
    console.log("batchInsert is failed, status = " + status);
})

update

update(values: ValuesBucket, predicates: RdbPredicates, callback: AsyncCallback<number>):void

Updates data in the RDB store based on the specified RdbPredicates object. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

const valueBucket = {
    "NAME": "Rose",
    "AGE": 22,
    "SALARY": 200.5,
    "CODES": new Uint8Array([1, 2, 3, 4, 5]),
}
let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Lisa")
rdbStore.update(valueBucket, predicates, function (err, rows) {
    if (err) {
        console.info("Failed to update data, err: " + err)
        return
    }
    console.log("Updated row count: " + rows)
})

update

update(values: ValuesBucket, predicates: RdbPredicates):Promise<number>

Updates data based on the specified RdbPredicates object. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

const valueBucket = {
    "NAME": "Rose",
    "AGE": 22,
    "SALARY": 200.5,
    "CODES": new Uint8Array([1, 2, 3, 4, 5]),
}
let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Lisa")
let promise = rdbStore.update(valueBucket, predicates)
promise.then(async (rows) => {
    console.log("Updated row count: " + rows)
}).catch((err) => {
    console.info("Failed to update data, err: " + err)
})

delete

delete(predicates: RdbPredicates, callback: AsyncCallback<number>):void

Deletes data from the RDB store based on the specified RdbPredicates object. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Lisa")
rdbStore.delete(predicates, function (err, rows) {
    if (err) {
        console.info("Failed to delete data, err: " + err)
        return
    }
    console.log("Deleted rows: " + rows)
})

delete

delete(predicates: RdbPredicates):Promise<number>

Deletes data from the RDB store based on the specified RdbPredicates object. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Lisa")
let promise = rdbStore.delete(predicates)
promise.then((rows) => {
    console.log("Deleted rows: " + rows)
}).catch((err) => {
    console.info("Failed to delete data, err: " + err)
})

query

query(predicates: RdbPredicates, columns: Array<string>, callback: AsyncCallback<ResultSet>):void

Queries data from the RDB store based on specified conditions. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Rose")
rdbStore.query(predicates, ["ID", "NAME", "AGE", "SALARY", "CODES"], function (err, resultSet) {
    if (err) {
        console.info("Failed to query data, err: " + err)
        return
    }
    console.log("ResultSet column names: " + resultSet.columnNames)
    console.log("ResultSet column count: " + resultSet.columnCount)
})

query

query(predicates: RdbPredicates, columns?: Array<string>):Promise<ResultSet>

Queries data from the RDB store based on specified conditions. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Rose")
let promise = rdbStore.query(predicates, ["ID", "NAME", "AGE", "SALARY", "CODES"])
promise.then((resultSet) => {
    console.log("ResultSet column names: " + resultSet.columnNames)
    console.log("ResultSet column count: " + resultSet.columnCount)
}).catch((err) => {
    console.info("Failed to query data, err: " + err)
})

querySql⁸⁺

querySql(sql: string, bindArgs: Array<ValueType>, callback: AsyncCallback<ResultSet>):void

Queries data in the RDB store using the specified SQL statement. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

rdbStore.querySql("SELECT * FROM EMPLOYEE CROSS JOIN BOOK WHERE BOOK.NAME = ?", ['sanguo'], function (err, resultSet) {
    if (err) {
        console.info("Failed to query data, err: " + err)
        return
    }
    console.log("ResultSet column names: " + resultSet.columnNames)
    console.log("ResultSet column count: " + resultSet.columnCount)
})

querySql⁸⁺

querySql(sql: string, bindArgs?: Array<ValueType>):Promise<ResultSet>

Queries data in the RDB store using the specified SQL statement. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let promise = rdbStore.querySql("SELECT * FROM EMPLOYEE CROSS JOIN BOOK WHERE BOOK.NAME = 'sanguo'")
promise.then((resultSet) => {
    console.log("ResultSet column names: " + resultSet.columnNames)
    console.log("ResultSet column count: " + resultSet.columnCount)
}).catch((err) => {
    console.info("Failed to query data, err: " + err)
})

executeSql⁸⁺

executeSql(sql: string, bindArgs: Array<ValueType>, callback: AsyncCallback<void>):void

Executes an SQL statement that contains specified arguments but returns no value. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

const SQL_CREATE_TABLE = "CREATE TABLE IF NOT EXISTS EMPLOYEE (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT NOT NULL, AGE INTEGER, SALARY REAL, CODES BLOB)"
rdbStore.executeSql(SQL_CREATE_TABLE, null, function(err) {
    if (err) {
        console.info("Failed to execute SQL, err: " + err)
        return
    }
    console.info('Create table done.')
})

executeSql⁸⁺

executeSql(sql: string, bindArgs?: Array<ValueType>):Promise<void>

Executes an SQL statement that contains specified arguments but returns no value. This API uses a promise to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

const SQL_DELETE_TABLE = "DELETE FROM test WHERE name = 'zhangsan'"
let promise = rdbStore.executeSql(SQL_DELETE_TABLE)
promise.then(() => {
    console.info('Delete table done.')
}).catch((err) => {
    console.info("Failed to execute SQL, err: " + err)
})

beginTransaction⁸⁺

beginTransaction():void

Starts the transaction before executing an SQL statement.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Example

import featureAbility from '@ohos.ability.featureAbility'
let context = featureAbility.getContext()
const STORE_CONFIG = { name: "RdbTest.db"}
data_rdb.getRdbStore(context, STORE_CONFIG, 1, async function (err, rdbStore) {
    rdbStore.beginTransaction()
	const valueBucket = {
		"name": "lisi",
		"age": 18,
		"salary": 100.5,
		"blobType": new Uint8Array([1, 2, 3]),
	}
	await rdbStore.insert("test", valueBucket)
	rdbStore.commit()
})

commit⁸⁺

commit():void

Commits the executed SQL statements.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Example

import featureAbility from '@ohos.ability.featureAbility'
let context = featureAbility.getContext()
const STORE_CONFIG = { name: "RdbTest.db"}
data_rdb.getRdbStore(context, STORE_CONFIG, 1, async function (err, rdbStore) {
    rdbStore.beginTransaction()
	const valueBucket = {
		"name": "lisi",
		"age": 18,
		"salary": 100.5,
		"blobType": new Uint8Array([1, 2, 3]),
	}
	await rdbStore.insert("test", valueBucket)
	rdbStore.commit()
})

rollBack⁸⁺

rollBack():void

Rolls back the SQL statements that have been executed.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Example

import featureAbility from '@ohos.ability.featureAbility'
let context = featureAbility.getContext()
const STORE_CONFIG = { name: "RdbTest.db"}
data_rdb.getRdbStore(context, STORE_CONFIG, 1, async function (err, rdbStore) {
    try {
		rdbStore.beginTransaction()
		const valueBucket = {
			"id": 1,
			"name": "lisi",
			"age": 18,
			"salary": 100.5,
			"blobType": new Uint8Array([1, 2, 3]),
		}
		await rdbStore.insert("test", valueBucket)
		rdbStore.commit()
	} catch (e) {
		rdbStore.rollBack()
	}
})

setDistributedTables⁸⁺

setDistributedTables(tables: Array<string>, callback: AsyncCallback<void>): void

Sets distributed tables. This API uses an asynchronous callback to return the result.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

rdbStore.setDistributedTables(["EMPLOYEE"], function (err) {
    if (err) {
        console.info('Failed to set distributed tables, err: ' + err)
        return
    }
    console.info('Set distributed tables successfully.')
})

setDistributedTables⁸⁺

setDistributedTables(tables: Array<string>): Promise<void>

Sets distributed tables. This API uses a promise to return the result.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

let promise = rdbStore.setDistributedTables(["EMPLOYEE"])
promise.then(() => {
    console.info("Set distributed tables successfully.")
}).catch((err) => {
    console.info("Failed to set distributed tables, err: " + err)
})

obtainDistributedTableName⁸⁺

obtainDistributedTableName(device: string, table: string, callback: AsyncCallback<string>): void

Obtains the distributed table name of a remote device based on the local table name of the device. The distributed table name is required when the RDB store of a remote device is queried.

NOTE

The value of device is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

import deviceManager from '@ohos.distributedHardware.deviceManager';
let dmInstance = null;
let deviceId = null;

deviceManager.createDeviceManager("com.example.appdatamgrverify", (err, manager) => {
    if (err) {
        console.log("create device manager failed, err=" + err);
        return;
    }
    dmInstance = manager;
    let devices = dmInstance.getTrustedDeviceListSync();
    deviceId = devices[0].deviceId;
})


rdbStore.obtainDistributedTableName(deviceId, "EMPLOYEE", function (err, tableName) {
    if (err) {
        console.info('Failed to obtain DistributedTableName, err: ' + err)
        return
    }
    console.info('Obtained distributed table name successfully, tableName=.' + tableName)
})

obtainDistributedTableName⁸⁺

obtainDistributedTableName(device: string, table: string): Promise<string>

Obtains the distributed table name of a remote device based on the local table name of the device. The distributed table name is required when the RDB store of a remote device is queried.

NOTE

The value of device is obtained by deviceManager.getTrustedDeviceListSync. The APIs of the deviceManager module are system interfaces and available only to system applications.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

import deviceManager from '@ohos.distributedHardware.deviceManager';
let dmInstance = null;
let deviceId = null;

deviceManager.createDeviceManager("com.example.appdatamgrverify", (err, manager) => {
    if (err) {
        console.log("create device manager failed, err=" + err);
        return;
    }
    dmInstance = manager;
    let devices = dmInstance.getTrustedDeviceListSync();
    deviceId = devices[0].deviceId;
})

let promise = rdbStore.obtainDistributedTableName(deviceId, "EMPLOYEE")
promise.then((tableName) => {
    console.info('Obtained distributed table name successfully, tableName= ' + tableName)
}).catch((err) => {
    console.info('Failed to obtain DistributedTableName, err: ' + err)
})

sync⁸⁺

sync(mode: SyncMode, predicates: RdbPredicates, callback: AsyncCallback<Array<[string, number]>>): void

Synchronizes data between devices. This API uses an asynchronous callback to return the result.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

import deviceManager from '@ohos.distributedHardware.deviceManager';
let dmInstance = null;
let deviceIds = [];

deviceManager.createDeviceManager("com.example.appdatamgrverify", (err, manager) => {
    if (err) {
        console.log("create device manager failed, err=" + err);
        return;
    }
    dmInstance = manager;
    let devices = dmInstance.getTrustedDeviceListSync();
    for (var i = 0; i < devices.length; i++) {
        deviceIds[i] = devices[i].deviceId;
    }
})

let predicates = new data_rdb.RdbPredicates('EMPLOYEE')
predicates.inDevices(deviceIds)
rdbStore.sync(data_rdb.SyncMode.SYNC_MODE_PUSH, predicates, function (err, result) {
    if (err) {
        console.log('Sync failed, err: ' + err)
        return
    }
    console.log('Sync done.')
    for (let i = 0; i < result.length; i++) {
        console.log('device=' + result[i][0] + ' status=' + result[i][1])
    }
})

sync⁸⁺

sync(mode: SyncMode, predicates: RdbPredicates): Promise<Array<[string, number]>>

Synchronizes data between devices. This API uses a promise to return the result.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Return value

Example

import deviceManager from '@ohos.distributedHardware.deviceManager';
let dmInstance = null;
let deviceIds = [];

deviceManager.createDeviceManager("com.example.appdatamgrverify", (err, manager) => {
    if (err) {
        console.log("create device manager failed, err=" + err);
        return;
    }
    dmInstance = manager;
    let devices = dmInstance.getTrustedDeviceListSync();
    for (var i = 0; i < devices.length; i++) {
        deviceIds[i] = devices[i].deviceId;
    }
})

let predicates = new data_rdb.RdbPredicates('EMPLOYEE')
predicates.inDevices(deviceIds)
let promise = rdbStore.sync(data_rdb.SyncMode.SYNC_MODE_PUSH, predicates)
promise.then((result) =>{
    console.log('Sync done.')
    for (let i = 0; i < result.length; i++) {
        console.log('device=' + result[i][0] + ' status=' + result[i][1])
    }
}).catch((err) => {
    console.log('Sync failed')
})

on('dataChange')⁸⁺

on(event: 'dataChange', type: SubscribeType, observer: Callback<Array<string>>): void

Registers an observer for this RDB store. When the data in the RDB store changes, a callback is invoked to return the data changes.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

function storeObserver(devices) {
    for (let i = 0; i < devices.length; i++) {
        console.log('device=' + devices[i] + ' data changed')
    }
}
try {
    rdbStore.on('dataChange', data_rdb.SubscribeType.SUBSCRIBE_TYPE_REMOTE, storeObserver)
} catch (err) {
    console.log('Failed to register observer')
}

off('dataChange')⁸⁺

off(event:'dataChange', type: SubscribeType, observer: Callback<Array<string>>): void

Unregisters the observer of the specified type from the RDB store. This API uses a callback to return the result.

System capability: SystemCapability.DistributedDataManager.RelationalStore.Core

Parameters

Example

function storeObserver(devices) {
    for (let i = 0; i < devices.length; i++) {
        console.log('device=' + devices[i] + ' data changed')
    }
}
try {
    rdbStore.off('dataChange', data_rdb.SubscribeType.SUBSCRIBE_TYPE_REMOTE, storeObserver)
} catch (err) {
    console.log('Failed to unregister observer')
}