HarmonyOS 应用开发之关系型数据库跨设备数据同步

   import relationalStore from '@ohos.data.relationalStore';

 import UIAbility from '@ohos.app.ability.UIAbility'; import window from '@ohos.window'; import { BusinessError } from "@ohos.base"; class EntryAbility extends UIAbility { onWindowStageCreate(windowStage: window.WindowStage) { const STORE_CONFIG: relationalStore.StoreConfig = { name: "RdbTest.db", securityLevel: relationalStore.SecurityLevel.S1 }; relationalStore.getRdbStore(this.context, STORE_CONFIG, (err: BusinessError, store: relationalStore.RdbStore) => { store.executeSql('CREATE TABLE IF NOT EXISTS EMPLOYEE (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT NOT NULL, AGE INTEGER, SALARY REAL, CODES BLOB)', (err) => { // 设置分布式同步表。 store.setDistributedTables(['EMPLOYEE']); // 进行数据的相关操作 }) }) } }

// 构造用于同步分布式表的谓词对象 
let predicates = new relationalStore.RdbPredicates('EMPLOYEE'); // 调用同步数据的接口 
if(store != undefined) { (store as relationalStore.RdbStore).sync(relationalStore.SyncMode.SYNC_MODE_PUSH, predicates, (err, result) => { // 判断数据同步是否成功 
if (err) { console.error(`Failed to sync data. Code:${err.code},message:${err.message}`); return; } console.info('Succeeded in syncing data.'); for (let i = 0; i < result.length; i++) { console.info(`device:${result[i][0]},status:${result[i][1]}`); } }) }

 let devices: string | undefined = undefined; try { // 调用分布式数据订阅接口，注册数据库的观察者 // 当分布式数据库中的数据发生更改时，将调用回调 
 if(store != undefined) { (store as relationalStore.RdbStore).on('dataChange', relationalStore.SubscribeType.SUBSCRIBE_TYPE_REMOTE, (storeObserver)=>{ if(devices != undefined){ for (let i = 0; i < devices.length; i++) { console.info(`The data of device:${devices[i]} has been changed.`); } } }); } } catch (err) { console.error('Failed to register observer. Code:${err.code},message:${err.message}'); } // 当前不需要订阅数据变化时，可以将其取消。
  try { if(store != undefined) { (store as relationalStore.RdbStore).off('dataChange', relationalStore.SubscribeType.SUBSCRIBE_TYPE_REMOTE, (storeObserver)=>{ }); } } catch (err) { console.error('Failed to register observer. Code:${err.code},message:${err.message}'); }

// 获取deviceIds
import deviceManager from '@ohos.distributedDeviceManager';
import { BusinessError } from '@ohos.base'

let dmInstance: deviceManager.DeviceManager;
let deviceId: string | undefined = undefined ;

try {
  dmInstance = deviceManager.createDeviceManager("com.example.appdatamgrverify");
  let devices = dmInstance.getAvailableDeviceListSync();

  deviceId = devices[0].networkId;

  // 构造用于查询分布式表的谓词对象
  let predicates = new relationalStore.RdbPredicates('EMPLOYEE');
  // 调用跨设备查询接口，并返回查询结果
  if(store != undefined && deviceId != undefined) {
    (store as relationalStore.RdbStore).remoteQuery(deviceId, 'EMPLOYEE', predicates, ['ID', 'NAME', 'AGE', 'SALARY', 'CODES'],
      (err: BusinessError, resultSet: relationalStore.ResultSet) => {
        if (err) {
          console.error(`Failed to remoteQuery data. Code:${err.code},message:${err.message}`);
          return;
        }
        console.info(`ResultSet column names: ${resultSet.columnNames}, column count: ${resultSet.columnCount}`);
      }
    )
  }
} catch (err) {
  let code = (err as BusinessError).code;
  let message = (err as BusinessError).message;
  console.error("createDeviceManager errCode:" + code + ",errMessage:" + message);
}