目录

批量数据写数据库场景

使用TaskPool进行频繁数据库操作

对于需要频繁数据库操作的场景，由于读写数据库存在耗时，因此推荐在子线程中操作，避免阻塞UI线程。

通过ArkTS提供的TaskPool能力，可以将数据库操作任务移到子线程中，实现如下。

  1. 创建多个子任务，支持数据库的创建、插入、查询和清除等操作。

  2. UI主线程发起数据库操作请求，在子线程中完成数据库的增删改查等操作。

import { relationalStore, ValuesBucket } from '@kit.ArkData';
import { taskpool } from '@kit.ArkTS';

@Concurrent
async function create(context: Context) {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  let store: relationalStore.RdbStore = await relationalStore.getRdbStore(context, CONFIG);
  console.info(`Get Store.db successfully!`);

  // 创建表
  const CREATE_TABLE_SQL = 'CREATE TABLE IF NOT EXISTS test (' +
    'id INTEGER PRIMARY KEY AUTOINCREMENT, ' +
    'name TEXT NOT NULL, ' +
    'age INTEGER, ' +
    'salary REAL, ' +
    'blobType BLOB)';
  await store.executeSql(CREATE_TABLE_SQL);
  console.info(`Create table test successfully!`);
}

@Concurrent
async function insert(context: Context, valueBucketArray: Array<relationalStore.ValuesBucket>) {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  let store: relationalStore.RdbStore = await relationalStore.getRdbStore(context, CONFIG);
  console.info(`Get Store.db successfully!`);

  // 数据插入
  await store.batchInsert('test', valueBucketArray as Object as Array<relationalStore.ValuesBucket>);
}

@Concurrent
async function query(context: Context): Promise<Array<relationalStore.ValuesBucket>> {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  let store: relationalStore.RdbStore = await relationalStore.getRdbStore(context, CONFIG);
  console.info(`Get Store.db successfully!`);

  // 获取结果集
  let predicates: relationalStore.RdbPredicates = new relationalStore.RdbPredicates('test');
  let resultSet = await store.query(predicates); // 查询所有数据
  console.info(`Query data successfully! row count:${resultSet.rowCount}`);
  let index = 0;
  let result = new Array<relationalStore.ValuesBucket>(resultSet.rowCount);
  resultSet.goToFirstRow();
  do {
    result[index++] = resultSet.getRow();
  } while (resultSet.goToNextRow());
  resultSet.close();
  return result;
}

@Concurrent
async function clear(context: Context) {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  await relationalStore.deleteRdbStore(context, CONFIG);
  console.info(`Delete Store.db successfully!`);
}

@Entry
@Component
struct Index {
  @State message: string = 'Hello World';

  build() {
    RelativeContainer() {
      Text(this.message)
        .id('HelloWorld')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .alignRules({
          center: { anchor: '__container__', align: VerticalAlign.Center },
          middle: { anchor: '__container__', align: HorizontalAlign.Center }
        })
        .onClick(async () => {
          let context: Context = this.getUIContext().getHostContext() as Context;

          // 数据准备
          const count = 5;
          let valueBucketArray = new Array<relationalStore.ValuesBucket>(count);
          for (let i = 0; i < count; i++) {
            let v: relationalStore.ValuesBucket = {
              id: i,
              name: 'zhangsan' + i,
              age: 20,
              salary: 5000 + 50 * i
            };
            valueBucketArray[i] = v;
          }
          await taskpool.execute(create, context);
          await taskpool.execute(insert, context, valueBucketArray);
          let index = 0;
          let ret = await taskpool.execute(query, context) as Array<relationalStore.ValuesBucket>;
          for (let v of ret) {
            console.info(`Row[${index}].id = ${v.id}`);
            console.info(`Row[${index}].name = ${v.name}`);
            console.info(`Row[${index}].age = ${v.age}`);
            console.info(`Row[${index}].salary = ${v.salary}`);
            index++;
          };
          await taskpool.execute(clear, context);
          this.message = 'success';
        })
    }
    .height('100%')
    .width('100%')
  }
}

使用Sendable进行大容量数据库操作

由于数据库数据跨线程传递存在耗时，数据量较大时会占用UI主线程。推荐使用Sendable封装数据库数据，以降低跨线程开销。

  1. 定义数据库中的数据格式，可以使用Sendable，以减少跨线程操作的耗时。

    export interface IValueBucket {
  id: number;
  name: string;
  age: number;
  salary: number;
}

@Sendable
export class SharedValuesBucket implements IValueBucket {
  public id: number = 0;
  public name: string = '';
  public age: number = 0;
  public salary: number = 0;

  constructor(v: IValueBucket) {
    this.id = v.id;
    this.name = v.name;
    this.age = v.age;
    this.salary = v.salary;
  }
}

  2. UI主线程发起数据库操作请求，在子线程完成数据的增删改查等操作。

    import { relationalStore, ValuesBucket } from '@kit.ArkData';
import { collections, taskpool } from '@kit.ArkTS';
import { IValueBucket, SharedValuesBucket } from './SharedValuesBucket';

@Concurrent
async function create(context: Context) {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  let store: relationalStore.RdbStore = await relationalStore.getRdbStore(context, CONFIG);
  console.info(`Get Store.db successfully!`);

  // 创建表
  const CREATE_TABLE_SQL = 'CREATE TABLE IF NOT EXISTS test (' +
    'id INTEGER PRIMARY KEY AUTOINCREMENT, ' +
    'name TEXT NOT NULL, ' +
    'age INTEGER, ' +
    'salary REAL, ' +
    'blobType BLOB)';
  await store.executeSql(CREATE_TABLE_SQL);
  console.info(`Create table test successfully!`);
}

@Concurrent
async function insert(context: Context, valueBucketArray: Array<relationalStore.ValuesBucket>) {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  let store: relationalStore.RdbStore = await relationalStore.getRdbStore(context, CONFIG);
  console.info(`Get Store.db successfully!`);

  // 数据插入
  await store.batchInsert('test', valueBucketArray as Object as Array<relationalStore.ValuesBucket>);
}

@Concurrent
async function query(context: Context): Promise<collections.Array<SharedValuesBucket | undefined>> {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  let store: relationalStore.RdbStore = await relationalStore.getRdbStore(context, CONFIG);
  console.info(`Get Store.db successfully!`);

  // 获取结果集
  let predicates: relationalStore.RdbPredicates = new relationalStore.RdbPredicates('test');
  let resultSet = await store.query(predicates); // 查询所有数据
  console.info(`Query data successfully! row count:${resultSet.rowCount}`);

  // 使用 collections.Array 作为 Sendable 容器存储结果
  let index = 0;
  let result = collections.Array.create<SharedValuesBucket | undefined>(resultSet.rowCount, undefined);
  resultSet.goToFirstRow();
  do {
    // 逐字段从 ResultSet 读取数据，封装为 IValueBucket
    let v: IValueBucket = {
      id: resultSet.getLong(resultSet.getColumnIndex('id')),
      name: resultSet.getString(resultSet.getColumnIndex('name')),
      age: resultSet.getLong(resultSet.getColumnIndex('age')),
      salary: resultSet.getDouble(resultSet.getColumnIndex('salary'))
    };
    // 包装为 @Sendable 类实例，支持跨线程引用传递
    result[index++] = new SharedValuesBucket(v);
  } while (resultSet.goToNextRow());
  resultSet.close();
  return result;
}

@Concurrent
async function clear(context: Context) {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  await relationalStore.deleteRdbStore(context, CONFIG);
  console.info(`Delete Store.db successfully!`);
}

@Entry
@Component
struct Index {
  @State message: string = 'Hello World';

  build() {
    RelativeContainer() {
      Text(this.message)
        .id('HelloWorld')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .alignRules({
          center: { anchor: '__container__', align: VerticalAlign.Center },
          middle: { anchor: '__container__', align: HorizontalAlign.Center }
        })
        .onClick(async () => {
          let context: Context = this.getUIContext().getHostContext() as Context;

          // 数据准备
          const count = 5;
          let valueBucketArray = collections.Array.create<SharedValuesBucket | undefined>(count, undefined);
          for (let i = 0; i < count; i++) {
            let v: IValueBucket = {
              id: i,
              name: 'zhangsan' + i,
              age: 20,
              salary: 5000 + 50 * i
            };
            valueBucketArray[i] = new SharedValuesBucket(v);
          }
          await taskpool.execute(create, context);
          await taskpool.execute(insert, context, valueBucketArray);
          let index = 0;
          let ret: collections.Array<SharedValuesBucket> =
            await taskpool.execute(query, context) as collections.Array<SharedValuesBucket>;
          for (let v of ret.values()) {
            console.info(`Row[${index}].id = ${v.id}`);
            console.info(`Row[${index}].name = ${v.name}`);
            console.info(`Row[${index}].age = ${v.age}`);
            console.info(`Row[${index}].salary = ${v.salary}`);
            index++;
          };
          await taskpool.execute(clear, context);
          this.message = 'success';
        })
    }
    .height('100%')
    .width('100%')
  }
}

复杂类实例对象使用Sendable进行大容量数据库操作

普通类实例对象的属性可持有Sendable类实例对象。

对于复杂的普通类实例对象，可以先将相应数据库数据字段封装为Sendable类实例对象，再由普通类实例对象持有，从而降低跨线程开销。

  1. 定义数据库中的数据格式，采用Sendable，减少跨线程耗时。

    export interface IValueBucket {
  id: number;
  name: string;
  age: number;
  salary: number;
}

@Sendable
export class SharedValuesBucket implements IValueBucket {
  public id: number = 0;
  public name: string = '';
  public age: number = 0;
  public salary: number = 0;

  constructor(v: IValueBucket) {
    this.id = v.id;
    this.name = v.name;
    this.age = v.age;
    this.salary = v.salary;
  }
}

  2. 定义普通类实例对象，持有Sendable类实例对象。

    import { SharedValuesBucket } from './SharedValuesBucket';
import { collections } from '@kit.ArkTS';

export class Material {
  public seq: number = 0;
  public materialName: string = '';
  // ... 省略其他属性
  public buckets: collections.Array<SharedValuesBucket | undefined>;

  constructor(seq: number, materialName: string, buckets: collections.Array<SharedValuesBucket | undefined>) {
    this.seq = seq;
    this.materialName = materialName;
    this.buckets = buckets;
  }

  getBuckets() : collections.Array<SharedValuesBucket | undefined>{
    return this.buckets;
  }

  setBuckets(buckets: collections.Array<SharedValuesBucket | undefined>) {
    this.buckets = buckets;
  }
}

  3. UI主线程发起数据库操作请求，在子线程进行数据的增删改查等操作。

    import { relationalStore, ValuesBucket } from '@kit.ArkData';
import { collections, taskpool } from '@kit.ArkTS';
import { IValueBucket, SharedValuesBucket } from './SharedValuesBucket';
import { Material } from './Material';

@Concurrent
async function create(context: Context): Promise<boolean> {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  try {
    // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
    let store: relationalStore.RdbStore = await relationalStore.getRdbStore(context, CONFIG);
    console.info('Get Store.db successfully!');

    // 创建表
    const CREATE_TABLE_SQL = 'CREATE TABLE IF NOT EXISTS test (' +
      'id INTEGER PRIMARY KEY AUTOINCREMENT, ' +
      'name TEXT NOT NULL, ' +
      'age INTEGER, ' +
      'salary REAL, ' +
      'blobType BLOB)';
    await store.executeSql(CREATE_TABLE_SQL);
    console.info('Create table test successfully!');
    return true;
  } catch (err) {
    console.error(`Create db failed, code: ${err.code}, message: ${err.message}`);
    return false;
  }
}

@Concurrent
async function insert(context: Context, valueBucketArray: collections.Array<SharedValuesBucket | undefined>) {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  let store: relationalStore.RdbStore = await relationalStore.getRdbStore(context, CONFIG);
  console.info('Get Store.db successfully!');

  // 数据插入
  await store.batchInsert('test', valueBucketArray as Object as Array<ValuesBucket>);
}

@Concurrent
async function query(context: Context): Promise<collections.Array<SharedValuesBucket | undefined>> {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  let store: relationalStore.RdbStore = await relationalStore.getRdbStore(context, CONFIG);
  console.info('Get Store.db successfully!');

  // 获取用于查询的谓词
  let predicates: relationalStore.RdbPredicates = new relationalStore.RdbPredicates('test');
  // 查询所有数据
  let resultSet = await store.query(predicates);
  console.info(`Query data successfully! row count:${resultSet.rowCount}`);
  let index = 0;
  let result = collections.Array.create<SharedValuesBucket | undefined>(resultSet.rowCount, undefined);
  resultSet.goToFirstRow();
  do {
    let value: IValueBucket = {
      id: resultSet.getLong(resultSet.getColumnIndex('id')),
      name: resultSet.getString(resultSet.getColumnIndex('name')),
      age: resultSet.getLong(resultSet.getColumnIndex('age')),
      salary: resultSet.getDouble(resultSet.getColumnIndex('salary'))
    };
    result[index++] = new SharedValuesBucket(value);
  } while (resultSet.goToNextRow());
  resultSet.close();
  return result;
}

@Concurrent
async function deleteStore(context: Context) {
  const CONFIG: relationalStore.StoreConfig = {
    name: 'Store.db',
    securityLevel: relationalStore.SecurityLevel.S1,
  };

  // 默认数据库文件路径为 context.databaseDir + "/rdb/" + StoreConfig.name
  await relationalStore.deleteRdbStore(context, CONFIG);
  console.info('Delete Store.db successfully!');
}

function initMaterial(): Material {
  // 数据准备
  const count = 5;
  let valueBucketArray = collections.Array.create<SharedValuesBucket | undefined>(count, undefined);
  for (let i = 0; i < count; i++) {
    let value: IValueBucket = {
      id: i,
      name: 'zhangsan' + i,
      age: 20,
      salary: 5000 + 50 * i
    };
    valueBucketArray[i] = new SharedValuesBucket(value);
  }
  let material = new Material(1, 'test', valueBucketArray);
  return material;
}

@Entry
@Component
struct Index {
  @State message: string = 'Hello World';

  build() {
    RelativeContainer() {
      Text(this.message)
        .id('HelloWorld')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .alignRules({
          center: { anchor: '__container__', align: VerticalAlign.Center },
          middle: { anchor: '__container__', align: HorizontalAlign.Center }
        })
        .onClick(async () => {
          let context: Context = this.getUIContext().getHostContext() as Context;
          let material = initMaterial();
          let ret = await taskpool.execute(create, context);
          if (!ret) {
            console.error('Create db failed.');
            return;
          }
          await taskpool.execute(insert, context, material.getBuckets());
          let index = 0;
          let resultSet: collections.Array<SharedValuesBucket> =
            await taskpool.execute(query, context) as collections.Array<SharedValuesBucket>;
          material.setBuckets(resultSet);
          for (let value of resultSet.values()) {
            console.info(`Row[${index}].id = ${value.id}`);
            console.info(`Row[${index}].name = ${value.name}`);
            console.info(`Row[${index}].age = ${value.age}`);
            console.info(`Row[${index}].salary = ${value.salary}`);
            index++;
          }
          await taskpool.execute(deleteStore, context);
        })
    }
    .height('100%')
    .width('100%')
  }
}