HarmonyOS 鸿蒙Next ArkTS语言教程入门学习第61天，创建，启动DataAbility。

1、创建DataAbility

实现DataAbility中Insert、Query、Update、Delete接口的业务内容。保证能够满足数据库存储业务的基本需求。

BatchInsert与ExecuteBatch接口已经在系统中实现遍历逻辑，依赖Insert、Query、Update、Delete接口逻辑，来实现数据的批量处理。

创建DataAbility的代码示例如下：

import featureAbility from '@ohos.ability.featureAbility'
import dataAbility from '@ohos.data.dataAbility'
import dataRdb from '@ohos.data.rdb'

const TABLE_NAME = 'book'
const STORE_CONFIG = { name: 'book.db' }
const SQL_CREATE_TABLE = 'CREATE TABLE IF NOT EXISTS book(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, introduction TEXT NOT NULL)'
let rdbStore: dataRdb.RdbStore = undefined

export default {
  onInitialized(abilityInfo) {
    console.info('DataAbility onInitialized, abilityInfo:' + abilityInfo.bundleName)
    let context = featureAbility.getContext()
    dataRdb.getRdbStore(context, STORE_CONFIG, 1, (err, store) => {
      console.info('DataAbility getRdbStore callback')
      store.executeSql(SQL_CREATE_TABLE, [])
      rdbStore = store
    });
  },
  insert(uri, valueBucket, callback) {
    console.info('DataAbility insert start')
    rdbStore.insert(TABLE_NAME, valueBucket, callback)
  },
  batchInsert(uri, valueBuckets, callback) {
    console.info('DataAbility batch insert start')
    for (let i = 0;i < valueBuckets.length; i++) {
      console.info('DataAbility batch insert i=' + i)
      if (i < valueBuckets.length - 1) {
        rdbStore.insert(TABLE_NAME, valueBuckets[i], (err: any, num: number) => {
          console.info('DataAbility batch insert ret=' + num)
        })
      } else {
        rdbStore.insert(TABLE_NAME, valueBuckets[i], callback)
      }
    }
  },
  query(uri, columns, predicates, callback) {
    console.info('DataAbility query start')
    let rdbPredicates = dataAbility.createRdbPredicates(TABLE_NAME, predicates)
    rdbStore.query(rdbPredicates, columns, callback)
  },
  update(uri, valueBucket, predicates, callback) {
    console.info('DataAbilityupdate start')
    let rdbPredicates = dataAbility.createRdbPredicates(TABLE_NAME, predicates)
    rdbStore.update(valueBucket, rdbPredicates, callback)
  },
  delete(uri, predicates, callback) {
    console.info('DataAbilitydelete start')
    let rdbPredicates = dataAbility.createRdbPredicates(TABLE_NAME, predicates)
    rdbStore.delete(rdbPredicates, callback)
  }
};

2、启动DataAbility

启动DataAbility会获取一个工具接口类对象（DataAbilityHelper）。启动DataAbility的示例代码如下：

// 作为参数传递的URI,与config中定义的URI的区别是多了一个"/",有三个"/",具体原因详见。
import featureAbility from '@ohos.ability.featureAbility'

let urivar = "dataability:///com.ix.DataAbility"
let DAHelper = featureAbility.acquireDataAbilityHelper(urivar);