HarmonyOS Next 入门实战
SQLite数据库HarmonyOS的关系型数据库基于SQLite
导入模块
import { relationalStore } from '@kit.ArkData';实现步骤：
[*]获取RdbStore对象，用于创建数据库，数据表，以及数据库升级等操作
let storeConfig = {name: 'Poetry.db',//数据库文件名securityLevel: relationalStore.SecurityLevel.S1,//安全级别encrypt: false, //是否加密，可选，默认不加密customDir: '', //自定义路径，可选，目录：context.databaseDir + '/rdb/' + customDirisReadOnly: false, //是否已只读方式打开，可选，默认false}relationalStore.getRdbStore(this.context, this.storeConfig).then(store => { //创建表 store.executeSql('sql') //判断版本 store.version}).catch((err: Error) => { })
[*]插入数据
let data :ValuesBucket={name:"zhangsan",age: 23,}store.insert("tableName",data).then((rowId)=>{//操作成功返回rowId,否则返回-1})store.batchInsert() //用于插入批量数据
[*]修改，删除数据：通过组件提供的谓词(Predicates)修改或删除组件
let data :ValuesBucket={name:"zhangsan",age: 26,}let predicates = new relationalStore.RdbPredicates("tableName")predicates.equalTo("name","zhangsan")//更新数据store.update(data,predicates).then((value)=>{})//删除数据store.delete(predicates).then((value)=>{})
[*]查询数据
let predicates = new relationalStore.RdbPredicates("tableName")predicates.equalTo("name","zhangsan")store.query(predicates).then((resultSet)=>{while (resultSet.goToNextRow()){ const name = resultSet.getString(resultSet.getColumnIndex("name")) const age = resultSet.getLong(resultSet.getColumnIndex("age"))}resultSet.close()})//也可以通过下面接口使用sql查询store.querySql(sql: string, bindArgs?: Array<ValueType>): Promise<ResultSet>;
[*]备份数据和恢复数据
//备份数据store.backup("backup.db")//恢复数据store.restore("backup.db")SmartDB
SmartDB与Android中的room组件类似，可以简化我们数据库操作的步骤，使代码更易维护。
安装和导入模块
//安装模块ohpm install @liushengyi/smartdb//导入模块import sql from "@liushengyi/smartdb"定义数据结构：
export class Poetry {@sql.SqlColumn(sql.ColumnType.TEXT)uuid?: string@sql.SqlColumn(sql.ColumnType.TEXT)title?: string@sql.SqlColumn(sql.ColumnType.TEXT)dynasty?: string@sql.SqlColumn(sql.ColumnType.TEXT)author?: string@sql.SqlColumn(sql.ColumnType.TEXT)introduction?: string@sql.SqlColumn(sql.ColumnType.TEXT)text?: string@sql.SqlColumn(sql.ColumnType.TEXT)textAlign?: string@sql.SqlColumn(sql.ColumnType.TEXT)translation?: string@sql.SqlColumn(sql.ColumnType.TEXT)rectify?: string@sql.SqlColumn(sql.ColumnType.TEXT)searchKey?: string}执行数据库操作：进行增删改查、事务操作
export class PoetryDao {public static TABLE_NAME = "Poetry"public static SQL_CREATE_TABLE = "CREATE TABLE IF NOT EXISTS `Poetry` (`uuid` TEXT NOT NULL, `title` TEXT, `dynasty` TEXT, `author` TEXT, `introduction` TEXT, `text` TEXT, `textAlign` TEXT, `translation` TEXT, `rectify` TEXT, `searchKey` TEXT, PRIMARY KEY(`uuid`))"@sql.SqlQuery(`select * from ${PoetryDao.TABLE_NAME} where uuid=#{uuid}`)@sql.ReturnType(Poetry)queryOne(@sql.Param('uuid') uuid: string): Promise<Poetry> { return sql.PromiseNull()}@sql.SqlQuery(`select count(*) from ${PoetryDao.TABLE_NAME} `)@sql.ReturnType(Number)queryCount(): Promise<Number> { return sql.PromiseNull()}@sql.SqlInsert(`insert into ${PoetryDao.TABLE_NAME} values (#{data.uuid},#{data.title},#{data.dynasty},#{data.author},#{data.introduction},#{data.text},#{data.textAlign},#{data.translation},#{data.rectify},#{data.searchKey})`)insert(@sql.Param('data') data: Poetry): Promise<void> { return sql.PromiseNull()} @sql.Transactional()async insertPoetryAll(list: Poetry[]) { for (let item of list) { await this.insert(item) }}}数据库管理：创建数据库、数据库升级
export class DatabaseManager {static readonly DATABASE_VERSION = 1static readonly DATABASE_NAME = 'poetry.db'static init(context: Context) { sql.dbHelper.initDb(context, DatabaseManager.DATABASE_NAME, DatabaseManager.DATABASE_VERSION, new DbOpenHelperImpl() )}}class DbOpenHelperImpl extends sql.DbOpenHelper {//创建数据库onCreate(db: relationalStore.RdbStore): void { db.executeSql(PoetryDao.SQL_CREATE_TABLE)}//升级数据onUpgrade(db: relationalStore.RdbStore, oldVersion: number, newVersion: number): void {}}最后在app启动的时候调用初始化方法
export default class EntryAbility extends UIAbility {onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void { hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onCreate'); DatabaseManager.init(this.context)}}数据初始化和使用
将json格式的数据插入到数据库中
poetryDao: PoetryDao = new PoetryDao()new Promise<boolean>(async (resolve, reject) => {try { let count = await this.poetryDao.queryCount() if (!count) { let list = await (await import("resources/rawfile/poetry.json")).default let poetryArray: Array<Poetry> = [] for (let item of list) { let poetry = item as Poetry poetry.uuid = util.generateRandomUUID() if (poetry.rectify) { poetry.rectify = JSON.stringify(poetry.rectify) } poetryArray.push(poetry) } this.poetryDao.insertPoetryAll(poetryArray) resolve(true) } else { resolve(false) }} catch (e) { reject(e)}})读取数据
//读取所有数据new PoetryDao().queryList().then((value) => {})//读取一条数据new PoetryDao().queryOne("id").then((value) => {})<hr>本文的技术设计和实现都是基于作者工作中的经验总结，如有错误，请留言指正，谢谢。
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