Relational Database
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.
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.
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
Name | Type | Mandatory | Description |
---|---|---|---|
context | Context | Yes | Application context. |
config | StoreConfig | Yes | Configuration of the RDB store. |
version | number | Yes | RDB store version. |
callback | AsyncCallback<RdbStore> | Yes | Callback invoked to return the RDB store obtained. |
Example
// Obtain the context.
import featureAbility from '@ohos.ability.featureAbility'
var 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.")
})
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 then call APIs to perform data operations.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
context | Context | Yes | Application context. |
config | StoreConfig | Yes | Configuration of the RDB store. |
version | number | Yes | RDB store version. |
Return value
Type | Description |
---|---|
Promise<RdbStore> | Promise used to return the RDB store obtained. |
Example
// Obtain the context.
import featureAbility from '@ohos.ability.featureAbility'
var 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)
})
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
Name | Type | Mandatory | Description |
---|---|---|---|
context | Context | Yes | Application context. |
name | string | Yes | Name of the RDB store to delete. |
callback | AsyncCallback<void> | Yes | Callback invoked to return the result. |
Example
// Obtain the context.
import featureAbility from '@ohos.ability.featureAbility'
var 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.")
})
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
Name | Type | Mandatory | Description |
---|---|---|---|
context | Context | Yes | Application context. |
name | string | Yes | Name of the RDB store to delete. |
Return value
Type | Description |
---|---|
Promise<void> | Promise used to return the result. |
Example
// Obtain the context.
import featureAbility from '@ohos.ability.featureAbility'
var 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)
})
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
Name | Type | Mandatory | Description |
---|---|---|---|
name | string | Yes | Database table name. |
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.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
devices | Array<string> | Yes | IDs of the remote devices in the same network. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
Example
let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.inDevices(['12345678abcde'])
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
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | ValueType | Yes | Value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | ValueType | Yes | Value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Type | Description |
---|---|
RdbPredicates | RdbPredicates with a left parenthesis. |
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
Type | Description |
---|---|
RdbPredicates | RdbPredicates with a right parenthesis. |
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
Type | Description |
---|---|
RdbPredicates | RdbPredicates with the OR condition. |
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
Type | Description |
---|---|
RdbPredicates | RdbPredicates with the AND condition. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | string | Yes | Value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | string | Yes | Value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | string | Yes | Value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
- 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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | string | Yes | Value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | string | Yes | Value to match the RdbPredicates. Wildcards are supported. * indicates zero, one, or multiple digits or characters. ? indicates a single digit or character. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
low | ValueType | Yes | Minimum value to match the RdbPredicates. |
high | ValueType | Yes | Maximum value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
low | ValueType | Yes | Minimum value to match the RdbPredicates. |
high | ValueType | Yes | Maximum value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | ValueType | Yes | Value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | ValueType | Yes | Value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | ValueType | Yes | Value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | ValueType | Yes | Value to match the RdbPredicates. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that can filter out duplicate records. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
value | number | Yes | Maximum number of records. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that specifies the maximum number of records. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
rowOffset | number | Yes | Number of rows to offset from the beginning. The value is a positive integer. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that specifies the start position of the returned result. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
fields | Array<string> | Yes | Names of columns to group. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that groups rows with the same 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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Name of the index column. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that specifies the index column. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | Array<ValueType> | Yes | Array of ValueTypes to match. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
field | string | Yes | Column name in the database table. |
value | Array<ValueType> | Yes | Array of ValueTypes to match. |
Return value
Type | Description |
---|---|
RdbPredicates | RdbPredicates object that matches the specified field. |
Example
let predicates = new data_rdb.RdbPredicates("EMPLOYEE")
predicates.notIn("NAME", ["Lisa", "Rose"])
RdbStore
Provides methods to manage an RDB store.
Before using the following APIs, use executeSql to initialize the database table structure and related data. For details, see RDB Development.
insert
insert(name: 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
Name | Type | Mandatory | Description |
---|---|---|---|
name | string | Yes | Name of the target table. |
values | ValuesBucket | Yes | Row of data to insert. |
callback | AsyncCallback<number> | Yes | Callback invoked to return the result. If the operation is successful, the row ID will be returned. Otherwise, -1 will be returned. |
Example
const valueBucket = {
"NAME": "Lisa",
"AGE": 18,
"SALARY": 100.5,
"CODES": new Uint8Array([1, 2, 3, 4, 5]),
}
rdbStore.insert("EMPLOYEE", valueBucket, function (err, ret) {
if (err) {
console.info("Failed to insert data, err: " + err)
return
}
console.log("Inserted first row: " + ret)
})
insert
insert(name: 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
Name | Type | Mandatory | Description |
---|---|---|---|
name | string | Yes | Name of the target table. |
values | ValuesBucket | Yes | Row of data to insert. |
Return value
Type | Description |
---|---|
Promise<number> | Promise used to return the result. If the operation is successful, the row ID will be returned. Otherwise, -1 will be returned. |
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(async (ret) => {
console.log("Inserted first row: " + ret)
}).catch((err) => {
console.log("Failed to insert data, err: " + err)
})
update
update(values: ValuesBucket, rdbPredicates: 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
Name | Type | Mandatory | Description |
---|---|---|---|
values | ValuesBucket | Yes | Data to update. The value specifies the row of data to be updated in the database. The key-value pair is associated with the column name in the target table. |
rdbPredicates | RdbPredicates | Yes | Update conditions specified by the RdbPredicates object. |
callback | AsyncCallback<number> | Yes | Callback invoked to return the number of rows updated. |
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, ret) {
if (err) {
console.info("Failed to update data, err: " + err)
return
}
console.log("Updated row count: " + ret)
})
update
update(values: ValuesBucket, rdbPredicates: RdbPredicates):Promise<number>
Updates data in 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
Name | Type | Mandatory | Description |
---|---|---|---|
values | ValuesBucket | Yes | Data to update. The value specifies the row of data to be updated in the database. The key-value pair is associated with the column name in the target table. |
rdbPredicates | RdbPredicates | Yes | Update conditions specified by the RdbPredicates object. |
Return value
Type | Description |
---|---|
Promise<number> | Promise used to return the number of rows updated. |
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 (ret) => {
console.log("Updated row count: " + ret)
}).catch((err) => {
console.info("Failed to update data, err: " + err)
})
delete
delete(rdbPredicates: 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
Name | Type | Mandatory | Description |
---|---|---|---|
rdbPredicates | RdbPredicates | Yes | Conditions specified by the RdbPredicates object for deleting data. |
callback | AsyncCallback<number> | Yes | Callback invoked to return the number of rows updated. |
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(rdbPredicates: RdbPredicates):Promise<number>
Deletes data from the RDB store based on the specified RdbPredicates object. This API uses a promise to return the result.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
rdbPredicates | RdbPredicates | Yes | Conditions specified by the RdbPredicates object for deleting data. |
Return value
Type | Description |
---|---|
Promise<number> | Promise used to return the number of rows updated. |
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(rdbPredicates: RdbPredicates, columns: Array<string>, callback: AsyncCallback<ResultSet>):void
Queries data in the RDB store based on specified conditions. This API uses an asynchronous callback to return the result.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
rdbPredicates | RdbPredicates | Yes | Query conditions specified by the RdbPredicates object. |
columns | Array<string> | Yes | Columns to query. If this parameter is not specified, the query applies to all columns. |
callback | AsyncCallback<ResultSet> | Yes | Callback invoked to return the result. If the operation is successful, a ResultSet object will be returned. |
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(rdbPredicates: RdbPredicates, columns?: Array<string>):Promise<ResultSet>
Queries data in the RDB store based on specified conditions. This API uses a promise to return the result.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
rdbPredicates | RdbPredicates | Yes | Query conditions specified by the RdbPredicates object. |
columns | Array<string> | No | Columns to query. If this parameter is not specified, the query applies to all columns. |
Return value
Type | Description |
---|---|
Promise<ResultSet> | Promise used to return the result. If the operation is successful, a ResultSet object will be returned. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
sql | string | Yes | SQL statement to run. |
bindArgs | Array<ValueType> | Yes | Arguments in the SQL statement. |
callback | AsyncCallback<ResultSet> | Yes | Callback invoked to return the result. If the operation is successful, a ResultSet object will be returned. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
sql | string | Yes | SQL statement to run. |
bindArgs | Array<ValueType> | No | Arguments in the SQL statement. |
Return value
Type | Description |
---|---|
Promise<ResultSet> | Promise used to return the result. If the operation is successful, a ResultSet object will be returned. |
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)
})
executeSql
executeSql(sql: string, bindArgs: Array<ValueType>, callback: AsyncCallback<void>):void
Runs the SQL statement that contains the specified parameters but does not return a value. This API uses an asynchronous callback to return the result.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
sql | string | Yes | SQL statement to run. |
bindArgs | Array<ValueType> | Yes | Arguments in the SQL statement. |
callback | AsyncCallback<void> | Yes | Callback invoked to return the result. |
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('Created table successfully.')
})
executeSql
executeSql(sql: string, bindArgs?: Array<ValueType>):Promise<void>
Runs the SQL statement that contains the specified parameters but does not return a value. This API uses a promise to return the execution result.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
sql | string | Yes | SQL statement to run. |
bindArgs | Array<ValueType> | No | Arguments in the SQL statement. |
Return value
Type | Description |
---|---|
Promise<void> | Promise used to return the result. |
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)"
let promise = rdbStore.executeSql(SQL_CREATE_TABLE)
promise.then(() => {
console.info('Created table successfully.')
}).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
rdbStore.beginTransaction()
const valueBucket = {
"name": "lisi",
"age": 18,
"salary": 100.5,
"blobType": new Uint8Array([1, 2, 3]),
}
rdbStore.insert("test", valueBucket, function (err, ret) {
if (err) {
console.info("Failed to insert data, err: " + err)
return
}
console.log("Inserted data successfully: " + ret)
})
rdbStore.commit()
commit8+
commit():void
Commits the executed SQL statements.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Example
rdbStore.beginTransaction()
const valueBucket = {
"name": "lisi",
"age": 18,
"salary": 100.5,
"blobType": new Uint8Array([1, 2, 3]),
}
rdbStore.insert("test", valueBucket, function (err, ret) {
if (err) {
console.info("Failed to insert data, err: " + err)
return
}
console.log("Inserted data successfully: " + ret)
})
rdbStore.commit()
rollBack8+
rollBack():void;
Rolls back the SQL statements that have been executed.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Example
try {
rdbStore.beginTransaction()
const valueBucket = {
"id": 1,
"name": "lisi",
"age": 18,
"salary": 100.5,
"blobType": new Uint8Array([1, 2, 3]),
}
rdbStore.insert("test", valueBucket, function (err, ret) {
if (err) {
console.info("Failed to insert data, err: " + err)
return
}
console.log("Inserted data successfully: " + ret)
})
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.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
tables | Array<string> | Yes | Names of the distributed tables to set. |
callback | AsyncCallback<void> | Yes | Callback invoked to return the result. |
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.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
tables | Array<string> | Yes | Names of the distributed tables to set. |
Return value
Type | Description |
---|---|
Promise<void> | Promise used to return the result. |
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 for a remote device based on the local table name. This API uses an asynchronous callback to return the result. The distributed table name is required when the database of a remote device is queried.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
device | string | Yes | Remote device. |
table | string | Yes | Local table name. |
callback | AsyncCallback<string> | Yes | Callback invoked to return the result. If the operation succeeds, the distributed table name of the remote device is returned. |
Example
rdbStore.obtainDistributedTableName("12345678abcde", "EMPLOYEE", function (err, tableName) {
if (err) {
console.info('Failed to obtain DistributedTableName, err: ' + err)
return
}
console.info('Obtained DistributedTableName successfully, tableName=.' + tableName)
})
obtainDistributedTableName8+
obtainDistributedTableName(device: string, table: string): Promise<string>
Obtains the distributed table name for a remote device based on the local table name. This API uses a promise to return the result. The distributed table name is used to query the RDB store of the remote device.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
device | string | Yes | Remote device. |
table | string | Yes | Local table name. |
Return value
Type | Description |
---|---|
Promise<string> | Promise used to return the result. If the operation succeeds, the distributed table name of the remote device is returned. |
Example
let promise = rdbStore.obtainDistributedTableName("12345678abcde", "EMPLOYEE")
promise.then((tableName) => {
console.info('Obtained DistributedTableName 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.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
mode | SyncMode | Yes | Data synchronization mode. The value can be push or pull. |
predicates | RdbPredicates | Yes | RdbPredicates object that specifies the data and devices to synchronize. |
callback | AsyncCallback<Array<[string, number]>> | Yes | Callback invoked to send the synchronization result to the caller. string indicates the device ID. number indicates the synchronization status of that device. The value 0 indicates a successful synchronization. Other values indicate a synchronization failure. |
Example
let predicates = new data_rdb.RdbPredicates('EMPLOYEE')
predicates.inDevices(['12345678abcde'])
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.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
mode | SyncMode | Yes | Data synchronization mode. The value can be push or pull. |
predicates | RdbPredicates | Yes | RdbPredicates object that specifies the data and devices to synchronize. |
Return value
Type | Description |
---|---|
Promise<Array<[string, number]>> | Promise used to return the synchronization result to the caller. string indicates the device ID. number indicates the synchronization status of that device. The value 0 indicates a successful synchronization. Other values indicate a synchronization failure. |
Example
let predicates = new data_rdb.RdbPredicates('EMPLOYEE')
predicates.inDevices(['12345678abcde'])
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
Name | Type | Mandatory | Description |
---|---|---|---|
event | string | Yes | The value is'dataChange', which indicates a data change event. |
type | SubscribeType | Yes | Type defined in SubscribeType. |
observer | Callback<Array<string>> | Yes | Observer that listens for the data changes in the RDB store. |
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 specified observer of the RDB store. This API uses a callback to return the result.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
event | string | Yes | The value is'dataChange', which indicates a data change event. |
type | SubscribeType | Yes | Type defined in SubscribeType. |
observer | Callback<Array<string>> | Yes | Data change observer registered. |
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')
}
StoreConfig
Manages the configuration of an RDB store.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Name | Type | Mandatory | Description |
---|---|---|---|
name | string | Yes | Database file name. |
ValueType
Defines the data types allowed.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Type | Description |
---|---|
number | Number. |
string | String. |
boolean | Boolean. |
ValuesBucket
Defines the types of the key and value in a KV pair.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Key Type | Value Type |
---|---|
string | ValueType| Uint8Array | null |
SyncMode8+
Defines the database synchronization mode.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Name | Default Value | Description |
---|---|---|
SYNC_MODE_PUSH | 0 | Data is pushed from a local device to a remote device. |
SYNC_MODE_PULL | 1 | Data is pulled from a remote device to a local device. |
SubscribeType8+
Defines the subscription type.
System capability: SystemCapability.DistributedDataManager.RelationalStore.Core
Name | Default Value | Description |
---|---|---|
SUBSCRIBE_TYPE_REMOTE | 0 | Subscribe to remote data changes. |