# Creating a DataAbility


To meet the basic requirements of the database storage service, implement the **Insert**, **Query**, **Update**, and **Delete** methods for a DataAbility. The **BatchInsert** and **ExecuteBatch** methods have already implemented the traversal logic, but not batch data processing.


The following sample code shows how to create a DataAbility:

```ts
import featureAbility from '@ohos.ability.featureAbility';
import dataAbility from '@ohos.data.dataAbility';
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import { AsyncCallback, BusinessError } from '@ohos.base';
import rdb from '@ohos.data.rdb';

const TABLE_NAME = 'book'
const STORE_CONFIG: rdb.StoreConfig = { 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: rdb.RdbStore | undefined = undefined

class DataAbility {
  onInitialized(want: Want) {
    console.info('DataAbility onInitialized, abilityInfo:' + want.bundleName)
    let context: common.BaseContext = {stageMode: featureAbility.getContext().stageMode}
    rdb.getRdbStore(context, STORE_CONFIG, 1, (err, store) => {
      console.info('DataAbility getRdbStore callback')
      store.executeSql(SQL_CREATE_TABLE, [])
      rdbStore = store
    });
  }
  insert(uri: string, valueBucket: rdb.ValuesBucket, callback: AsyncCallback<number>) {
    console.info('DataAbility insert start')
    if (rdbStore) {
      rdbStore.insert(TABLE_NAME, valueBucket, callback)
    }
  }
  batchInsert(uri: string, valueBuckets: Array<rdb.ValuesBucket>, callback: AsyncCallback<number>) {
    console.info('DataAbility batch insert start')
    if (rdbStore) {
      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: BusinessError, num: number) => {
            console.info('DataAbility batch insert ret=' + num)
          })
        } else {
          rdbStore.insert(TABLE_NAME, valueBuckets[i], callback)
        }
      }
    }
  }
  query(uri: string, columns: Array<string>, predicates: dataAbility.DataAbilityPredicates,
        callback: AsyncCallback<rdb.ResultSet>) {
    console.info('DataAbility query start')
    let rdbPredicates = dataAbility.createRdbPredicates(TABLE_NAME, predicates)
    if (rdbStore) {
      rdbStore.query(rdbPredicates, columns, callback)
    }
  }
  update(uri: string, valueBucket: rdb.ValuesBucket, predicates: dataAbility.DataAbilityPredicates,
         callback: AsyncCallback<number>) {
    console.info('DataAbilityupdate start')
    let rdbPredicates = dataAbility.createRdbPredicates(TABLE_NAME, predicates)
    if (rdbStore) {
      rdbStore.update(valueBucket, rdbPredicates, callback)
    }
  }
  delete(uri: string, predicates: dataAbility.DataAbilityPredicates, callback: AsyncCallback<number>) {
    console.info('DataAbilitydelete start')
    let rdbPredicates = dataAbility.createRdbPredicates(TABLE_NAME, predicates)
    if (rdbStore) {
      rdbStore.delete(rdbPredicates, callback)
    }
  }
}

export default new DataAbility()
```