鸿蒙实现数据管理

- 1、鸿蒙实现数据管理的三种方式
- 2、用户首选项
- 3、键值型数据管理
- - 3.1、获取KVManager实例，用于管理数据库对象
  - 3.2、创建并获取键值数据库
  - 3.3、调用put()方法向键值数据库中插入数据
  - 3.4、调用get()方法获取指定键的值
  - 3.5、调用delete()方法删除指定键值的数据
- 4、关系型数据管理
- - 4.1、导入模块
  - 4.2、在abliity入口文件的生命周期函数onWindowStageCreat中添加初始化代码
  - 4.3、RdbUtils工具类
  - 4.4、创建数据库
  - 4.5、插入数据
  - 4.6、查询数据
  - 4.7、修改和删除数据
  - 4.8、删除数据库

1、鸿蒙实现数据管理的三种方式

用户首选项
键值型数据管理
关系型数据管理

在这里插入图片描述

2、用户首选项

import dataPreferences from '@ohos.data.preferences';
import preferences from '@ohos.data.preferences';
import { Log } from './Log';
import { ValueType } from '@kit.ArkData';

/**
 * 用户首选项工具类
 */
export class PreferencesUtil {
  static mPreferences ?: dataPreferences.Preferences

  /**
   * 初始化
   * @param context
   */
  static init(context: Context) {
    try {
      dataPreferences.getPreferences(context, 'Looper_Sp', (err, preferences) => {
        if (err) {
          Log.error(`Failed to get preferences. Code:${err.code},message:${err.message}`);
          return;
        }
        PreferencesUtil.mPreferences = preferences
        Log.info('Succeeded in getting preferences.');
        // 进行相关数据操作
      })
    } catch (err) {
      Log.error(`Failed to get preferences. Code:${err.code},message:${err.message}`);
    }
  }

  /**
   * 写数据
   * @param isFlush 是否持久化
   */
  static writeData(key: string, value: ValueType, isFlush: boolean): Promise<boolean> {
    return new Promise((resolve, reject) => {
      try {
        PreferencesUtil.mPreferences?.put(key, value, (err) => {
          if (err) {
            Log.error(`Failed to put data. Code:${err.code}, message:${err.message}`);
            reject(false);
            return;
          }
          Log.info('Succeeded in putting data.');
          if (isFlush) {
            PreferencesUtil.flushData()
          }
          resolve(true);
        })
      } catch (err) {
        Log.error(`Failed to check the key 'startup'. Code:${err.code}, message:${err.message}`);
        reject(false);
      }
    });
  }

  /**
   * 读取数据
   */
  static readData<D>(key: string): Promise<D> {
    return new Promise((resolve, reject) => {
      if (PreferencesUtil.mPreferences == null) {
        reject(new Error("mPreferences is null"));
      } else {
        PreferencesUtil.mPreferences.get(key, "", (err, value) => {
          if (err) {
            reject(err);
            return;
          }
          resolve(value as D);
        })
      }
    });
  }

  /**
   * 删除数据
   * @param isFlush 是否持久化
   */
  static delData(key: string, isFlush: boolean): Promise<string> {
    return new Promise((resolve, reject) => {
      if (PreferencesUtil.mPreferences == null) {
        reject(new Error("mPreferences is null"));
      } else {
        PreferencesUtil.mPreferences.delete(key, (err, value) => {
          if (err) {
            reject(err);
            return;
          }
          if (isFlush) {
            PreferencesUtil.flushData()
          }
          resolve("删除成功");
        })
      }
    });
  }

  /**
   * 删除整个库
   * @param isFlush 是否持久化
   */
  static delDB(context: Context, storeName: string): Promise<string> {
    return new Promise((resolve, reject) => {
      dataPreferences.deletePreferences(context, storeName, (err, value) => {
        if (err) {
          reject(err);
          return;
        }
        resolve("删除成功");
      })
    });
  }

  /**
   * 持久化
   */
  static flushData() {
    if (PreferencesUtil.mPreferences != null) {
      try {
        PreferencesUtil.mPreferences.flush((err) => {
          if (err) {
            Log.error(`Failed to flush. Code:${err.code}, message:${err.message}`);
            return;
          }
          Log.info('Succeeded in flushing.');
        })
      } catch (err) {
        Log.error(`Failed to flush. Code:${err.code}, message:${err.message}`);
      }
    }
  }
}

let preferencesUtil = new PreferencesUtil()

export default preferencesUtil as PreferencesUtil

//下面首选项的方法可以在这里面执行，页面栈创建时就初始化用户首选项，就可以直接在代码中使用了
onWindowStageCreate(ability, windowStage) {
PreferencesUtil.init(this.context)
console.info(TAG, “onWindowStageCreate ability:” + JSON.stringify(ability));
console.info(TAG, “onWindowStageCreate windowStage:” + JSON.stringify(windowStage));
}
//sp储存初始化
PreferencesUtil.init(this.context)
//写入信息
PreferencesUtil.writeData("zzz", "bbb", true)
//读取信息
PreferencesUtil.readData<string>("zzz").then(res => {
      Log.info("读取数据:" + res)
    })

3、键值型数据管理

3.1、获取KVManager实例，用于管理数据库对象

// 导入模块
import { distributedKVStore } from '@kit.ArkData';
 
// Stage模型
import { window } from '@kit.ArkUI';
import { UIAbility } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';
 
let kvManager: distributedKVStore.KVManager | undefined = undefined;
 
export default class EntryAbility extends UIAbility {
  onCreate() {
    let context = this.context;
    const kvManagerConfig: distributedKVStore.KVManagerConfig = {
      context: context,
      bundleName: 'com.example.datamanagertest'
    };
    try {
      // 创建KVManager实例
      kvManager = distributedKVStore.createKVManager(kvManagerConfig);
      console.info('Succeeded in creating KVManager.');
      // 继续创建获取数据库
    } catch (e) {
      let error = e as BusinessError;
      console.error(`Failed to create KVManager. Code:${error.code},message:${error.message}`);
    }
  }
}
if (kvManager !== undefined) {
   kvManager = kvManager as distributedKVStore.KVManager;
  //进行后续操作
  //...
}

3.2、创建并获取键值数据库

let kvStore: distributedKVStore.SingleKVStore | undefined = undefined;
try {
  const options: distributedKVStore.Options = {
    createIfMissing: true,
    encrypt: false,
    backup: false,
    autoSync: false,
    // kvStoreType不填时，默认创建多设备协同数据库
    kvStoreType: distributedKVStore.KVStoreType.SINGLE_VERSION,
    // 多设备协同数据库：kvStoreType: distributedKVStore.KVStoreType.DEVICE_COLLABORATION,
    securityLevel: distributedKVStore.SecurityLevel.S1
  };
  kvManager.getKVStore<distributedKVStore.SingleKVStore>('storeId', options, (err, store: distributedKVStore.SingleKVStore) => {
    if (err) {
      console.error(`Failed to get KVStore: Code:${err.code},message:${err.message}`);
      return;
    }
    console.info('Succeeded in getting KVStore.');
    kvStore = store;
    // 请确保获取到键值数据库实例后，再进行相关数据操作
  });
} catch (e) {
  let error = e as BusinessError;
  console.error(`An unexpected error occurred. Code:${error.code},message:${error.message}`);
}
if (kvStore !== undefined) {
  kvStore = kvStore as distributedKVStore.SingleKVStore;
    //进行后续操作
    //...
}

3.3、调用put()方法向键值数据库中插入数据

const KEY_TEST_STRING_ELEMENT = 'key_test_string';
const VALUE_TEST_STRING_ELEMENT = 'value_test_string';
try {
  kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT, (err) => {
    if (err !== undefined) {
      console.error(`Failed to put data. Code:${err.code},message:${err.message}`);
      return;
    }
    console.info('Succeeded in putting data.');
  });
} catch (e) {
  let error = e as BusinessError;
  console.error(`An unexpected error occurred. Code:${error.code},message:${error.message}`);
}

说明：

当Key值存在时，put()方法会修改其值，否则新增一条数据。

3.4、调用get()方法获取指定键的值

try {
  kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT, (err) => {
    if (err !== undefined) {
      console.error(`Failed to put data. Code:${err.code},message:${err.message}`);
      return;
    }
    console.info('Succeeded in putting data.');
    kvStore = kvStore as distributedKVStore.SingleKVStore;
    kvStore.get(KEY_TEST_STRING_ELEMENT, (err, data) => {
      if (err != undefined) {
        console.error(`Failed to get data. Code:${err.code},message:${err.message}`);
        return;
      }
      console.info(`Succeeded in getting data. Data:${data}`);
    });
  });
} catch (e) {
  let error = e as BusinessError;
  console.error(`Failed to get data. Code:${error.code},message:${error.message}`);
}

3.5、调用delete()方法删除指定键值的数据

try {
  kvStore.put(KEY_TEST_STRING_ELEMENT, VALUE_TEST_STRING_ELEMENT, (err) => {
    if (err !== undefined) {
      console.error(`Failed to put data. Code:${err.code},message:${err.message}`);
      return;
    }
    console.info('Succeeded in putting data.');
    kvStore = kvStore as distributedKVStore.SingleKVStore;
    kvStore.delete(KEY_TEST_STRING_ELEMENT, (err) => {
      if (err !== undefined) {
        console.error(`Failed to delete data. Code:${err.code},message:${err.message}`);
        return;
      }
      console.info('Succeeded in deleting data.');
    });
  });
} catch (e) {
  let error = e as BusinessError;
  console.error(`An unexpected error occurred. Code:${error.code},message:${error.message}`);
}

4、关系型数据管理

4.1、导入模块

import relationalStore from '@ohos.data.relationalStore'; // 导入模块

4.2、在abliity入口文件的生命周期函数onWindowStageCreat中添加初始化代码

const STORE_CONFIG = {
      name: 'RdbTest.db', // 数据库文件名
      securityLevel: relationalStore.SecurityLevel.S1 // 数据库安全级别
    };

    relationalStore.getRdbStore(this.context, STORE_CONFIG, (err, store) => {
      if (err) {
        console.error(`Failed to get RdbStore. Code:${err.code}, message:${err.message}`);
        return;
      }
      console.info(`Succeeded in getting RdbStore.`);
      //保存store, 方便后面我们对数据库的操作
      RdbUtils.setStore(store)

    });

4.3、RdbUtils工具类

import relationalStore from '@ohos.data.relationalStore';
export default class RdbUtils {
  private static rdbStore: relationalStore.RdbStore;
  static setStore(store: relationalStore.RdbStore) {
    RdbUtils.rdbStore = store;
  }
  static getStore(): relationalStore.RdbStore {
    return RdbUtils.rdbStore;
  }
}

4.4、创建数据库

import relationalStore from '@ohos.data.relationalStore';
export default class RdbUtils {
  ...
  static executeSql(sql: string): Promise<void> {
    return RdbUtils.getStore().executeSql(sql);
  }
  ...
}

示例：

import RdbUtils from '../common/rdbUtils/RdbUtils';
@Entry
@Component
struct Index {
  build() {
    Row() {
      Column() {
        Button('创建数据库表')
          .onClick(() => {
            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)'; // 建表Sql语句
            RdbUtils.executeSql(SQL_CREATE_TABLE)
            .then(() =>{
                openDialog('successfully created table')
              }).catch((err) => {
              openDialog(err);
            })
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}

function openDialog(text: string) {
  AlertDialog.show(
    {
      title: 'title',
      message: text,
      autoCancel: true,
      alignment: DialogAlignment.Bottom,
      offset: { dx: 0, dy: -20 },
    }
  )
}

4.5、插入数据

import relationalStore from '@ohos.data.relationalStore';
export default class RdbUtils {
  ...
  static insert(tableName: string, data: any): Promise<number> {
    return RdbUtils.getStore().insert(tableName, data);
  }
  ...
}

示例：

import RdbUtils from '../common/rdbUtils/RdbUtils';
@Entry
@Component
struct Index {
  build() {
    Row() {
      Column() {
        ...
        Button('插入数据')
          .onClick(() => {
            const valueBucket = {
              'NAME': 'Lisa',
              'AGE': 18,
              'SALARY': 100.5,
              'CODES': new Uint8Array([1, 2, 3, 4, 5])
            };
            RdbUtils.insert('EMPLOYEE', valueBucket)
              .then((updateNumber) => {
                openDialog('已插入数据:' + updateNumber)
            }).catch((error) => {
              openDialog('error: ' + error)
            })
          })
        ...
      }
      .width('100%')
    }
    .height('100%')
  }
}
...

4.6、查询数据

static queryAll(): Promise<Array<Employee>> {
    let predicates = new relationalStore.RdbPredicates('EMPLOYEE');
    return new Promise<Array<Employee>>((resolve, reject) => {
      RdbUtils.getStore().query(predicates).then((result) => {
        let employees = new Array<Employee>();
        while (result.goToNextRow()) {
          let employee = new Employee(
            result.getLong(0),
            result.getString(1),
            result.getLong(2),
            result.getDouble(3),
            result.getBlob(4)
          );
          employees.push(employee);
        }
        resolve(employees);
      }).catch((error) => {
        reject(error)
      })
    })
  }

该方法将通过RdbUtils.getStore().query(predicates)获取的结果集封装到Employee类中，然后通过Promise进行返回。

实体类Employee：

export default class Employee {
  id: number; // 员工ID
  name: string; // 姓名
  age: number | null; // 年龄，允许为null
  salary: number | null; // 工资，允许为null
  codes: Uint8Array | null; // 二进制数据，用于存储 BLOB 类型，允许为null

  constructor(id: number, name: string, age: number | null, salary: number | null, codes: Uint8Array | null) {
    this.id = id;
    this.name = name;
    this.age = age;
    this.salary = salary;
    this.codes = codes;
  }
}

示例：

import RdbUtils from '../common/rdbUtils/RdbUtils';
@Entry
@Component
struct Index {
  build() {
    Row() {
      Column() {
        ...
        Button('查询数据')
          .onClick(() => {
            RdbUtils.queryAll()
              .then((employees: Array<Employee>) => {
                openDialog('employees: ' + JSON.stringify(employees))
              }).catch((error) => {
              openDialog('error' + error.toString())
            })
          })
        ...
      }
      .width('100%')
    }
    .height('100%')
  }
}
...

4.7、修改和删除数据

在工具包中添加：

...
  static deleteById(id: number) {
    let predicates = new relationalStore.RdbPredicates('EMPLOYEE');
    predicates.equalTo('ID', id)
    return RdbUtils.getStore().delete(predicates);
  }

  static updateById(id: number, data: any) {
    let predicates = new relationalStore.RdbPredicates('EMPLOYEE');
    predicates.equalTo('ID', id)
    return RdbUtils.getStore().update(data, predicates);
  }
...

      	Button('修改数据')
          .onClick(() => {
            const valueBucket = {
              'NAME': 'Rose',
              'AGE': 999,
              'SALARY': 100.5,
              'CODES': new Uint8Array([1, 2, 3, 4, 5])
            };
            RdbUtils.updateById(1, valueBucket)
              .then((updateNumber) => {
                openDialog('已更新数据:' + updateNumber.toString())
              }).catch((err) => {
              openDialog(err)
            })
          })

        Button('删除数据')
          .onClick(() => {
            RdbUtils.deleteById(1)
              .then((updateNumber) => {
                openDialog('已删除数据:' + updateNumber.toString())
              }).catch((err) => {
              openDialog(err)
            })
          })

4.8、删除数据库

export default class EntryAbility extends UIAbility {
  ...
  onDestroy() {
    hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onDestroy');
    relationalStore.deleteRdbStore(this.context, 'RdbTest.db', (err) => {
      if (err) {
        console.error(`Failed to delete RdbStore. Code:${err.code}, message:${err.message}`);
        return;
      }
      console.info('Succeeded in deleting RdbStore.');
    });
  }
  ....
}