Harmony OSArkUIDemo关系数据库基本使用

Posted 2022-05-16 华为开发者论坛

在HarmonyOS 中关系数据库的增删改查是非常常见的一种技术，今天进行写一个demo对数据的增删改查进行详细的讲解，在开发之前我们需要学习“​​关系数据库​​”,“​​结果集​​”这两篇开发文档，接下来我们分为“Api使用”，“demo实现”，“运行效果”三个步骤进行描述

1. Api使用

1.1创建数据库

import dataRdb from @ohos.data.rdb
const STORE_CONFIG = name: "RdbTest.db" 
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)"
let promise = dataRdb.getRdbStore(STORE_CONFIG, 1);
promise.then(async (rdbStore) => 
    rdbStore.executeSql(SQL_CREATE_TABLE, null)
).catch((err) => 
    expect(null).assertFail();
)

1.2 插入数据

const valueBucket = 
    "NAME": "Lisa",
    "AGE": 18,
    "SALARY": 100.5,
    "CODES": new Uint8Array([1, 2, 3, 4, 5]),

rdbStore.insert("EMPLOYEE", valueBucket, function (err, ret) 
    expect(1).assertEqual(ret)
console.log(TAG + "insert first done: " + ret))

1.3 删除数据

let predicates = new dataRdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Lisa")
rdbStore.delete(predicates, function (err, rows) 
    console.log(TAG + "delete rows: " + rows))

1.4 修改数据

const valueBucket = 
    "NAME": "Rose",
    "AGE": 22,
    "SALARY": 200.5,
    "CODES": new Uint8Array([1, 2, 3, 4, 5]),

let predicates = new dataRdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Lisa")
rdbStore.update(valueBucket, predicates, function (err, ret) 
    console.log(TAG + "updated row count: " + ret))

1.5 查询数据

let predicates = new dataRdb.RdbPredicates("EMPLOYEE")
predicates.equalTo("NAME", "Rose")
rdbStore.query(predicates, ["ID", "NAME", "AGE", "SALARY", "CODES"], function (err, resultSet) 
    console.log(TAG + "resultSet column names:" + resultSet.columnNames)
console.log(TAG + "resultSet column count:" + resultSet.columnCount))
复制

1.6 结果集处理

resultSet.goToFirstRow()
const id = resultSet.getLong(resultSet.getColumnIndex("ID"))
const name = resultSet.getString(resultSet.getColumnIndex("NAME"))
const age = resultSet.getLong(resultSet.getColumnIndex("AGE"))
const salary = resultSet.getDouble(resultSet.getColumnIndex("SALARY"))
复制

2. Demo实现

我们写五个text分别“创建数据库”，“插入数据”，“查询数据”，“修改数据”，“删除数据”，依次实现相应的点击事件，全部代码如下

import dataRdb from @ohos.data.rdb

@Entry
@Component
struct MyRdb 
  rdb: dataRdb.RdbStore;
  @State name: string= "Lisa"


  private CreateRdbStore() 
    var that=this;
    dataRdb.getRdbStore(  name: "XiLeiRgb.db" , 1, function (err, rdbStore) 
      if (err) 
        console.log(获取失败 + err)
       else 
        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)"
        rdbStore.executeSql(SQL_CREATE_TABLE, null)
        console.log(创建成功)
        that.rdb=rdbStore;
      
    )

  

  private insertData() 
    const valueBucket = 
      "NAME": "Lisa",
      "AGE": 18,
      "SALARY": 100.5,
      "CODES": new Uint8Array([1, 2, 3, 4, 5]),
    
    let promise = this.rdb.insert("EMPLOYEE", valueBucket)
    promise.then(async (ret) => 
      console.log( "插入成功==>>insert first done: " + ret)
      this.name="Lisa";
    ).catch((err) => 

    )


  

  private SelectData() 
    let predicates = new dataRdb.RdbPredicates("EMPLOYEE")
    predicates.equalTo("NAME", this.Harmony OS — ListContainer列表

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