【Harmony OS】【ArkUI】【Demo】关系数据库基本使用
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)})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"))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@Componentstruct 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.name) console.log("查询条件====>"+this.name) this.rdb.query(predicates, ["ID", "NAME", "AGE", "SALARY", "CODES"], function (err, resultSet) { console.log("查询成功==>>resultSet column names:" + resultSet.columnNames) console.log("查询成功==>>resultSet column count:" + resultSet.columnCount) if(resultSet.rowCount>0){ 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")) console.log( "id===>" + id+"===name==>"+name+"==age==>"+age+"==salary==>"+JSON.toString(salary)) }else{ console.log("暂无数据") } }) } private updateData() { var that=this; let 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", this.name) that.rdb.update(valueBucket, predicates, function (err, ret) { console.log("修改成功==>>updated row count: " + ret) that.name = "Rose"; }) } private deleteData() { let that=this let predicates = new dataRdb.RdbPredicates("EMPLOYEE") predicates.equalTo("NAME", this.name) that.rdb.delete(predicates, function (err, rows) { console.log("删除成功===>>delete rows: " + rows) }) } build() { Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) { Text('创建数据库') .fontSize(50) .onClick(this.CreateRdbStore.bind(this)) .fontWeight(FontWeight.Bold) Text('插入数据') .fontSize(50) .onClick(this.insertData.bind(this)) .backgroundColor(Color.Red) .fontWeight(FontWeight.Bold) Text('查询数据') .fontSize(50) .onClick(this.SelectData.bind(this)) .backgroundColor(Color.White) .fontWeight(FontWeight.Bold) Text('修改数据') .fontSize(50) .onClick(this.updateData.bind(this)) .backgroundColor(Color.Red) .fontWeight(FontWeight.Bold) Text('删除数据') .fontSize(50) .onClick(this.deleteData.bind(this)) .backgroundColor(Color.White) .fontWeight(FontWeight.Bold) } .width('100%') .height('100%') }}界面效果如下所示
3. 运行效果
我们依次点击“创建数据库”，“插入数据”，“查询数据”，“修改数据”，“查询数据”，“删除数据”，“查询数据”的效果如下
更多相关学习资料：
https://developer.huawei.com/consumer/cn/forum/topic/0202798055729860273?fid=0102683795438680754?ha_source=zzh