uniapp 本地数据库多端适配实例(根据运行环境自动选择适配器)

项目有个需求，需要生成app和小程序，app支持离线数据库，如果当前没有网络提醒用户开启离线模式，所以就随便搞了下，具体的思路就是： 一个接口和多个实现类（类似后端的模板设计模式），例如sqlite实现类，indexedDB实现类等等，根据环境动态选用具体的实现类

indexedDB有些方法没有改，sqlite没有测试，此处就是提供一个思路，只是用来学习和研究着玩了

目录

class类

BaseApi

import type LocalDB from '@/class/DbClass'
import { tableConfig } from '@/enums/DbEnums'
import { CallBackFunType } from '@/utils/request'
class BaseApi {public localDB: LocalDB;public table: string;public hasTable: boolean;constructor(table: string, localDB: LocalDB){this.table = tablethis.hasTable = falsethis.localDB = localDBif(this.localDB.Db().isOpen()){this.localDB.Db().hasTable(table).then((res:any) => {this.hasTable = res}).catch((res: any) => {console.log("构造初始化失败， table: " + this.table)})}}public getTable(): string{return this.table;}public getHasTable(): boolean{return this.hasTable;}public setHasTable(hasTable:boolean){this.hasTable = hasTable;}/*** 验证是否存在表信息*/public async verifyTable(init: boolean = false): Promise<CallBackFunType<any>>{if(!this.getHasTable() && init){const res = await this.init();if(!res){return new CallBackFunType({}).fail('初始化数据库失败')}else {return new CallBackFunType({}).success('初始化数据库成功');}}return new CallBackFunType({}).success('存在数据库');}/*** 初始化*/public async init(): Promise<boolean>{// 浏览器不能直接新建，需要适配const res = await this.localDB.Db().createTable(this.table, tableConfig[this.table])return res;}
}export default BaseApi;

DbClass

import type SqlAbapter from '@/plugins/db/SqlAbapter'// 根据平台选择适配器
class LocalDB {private db : SqlAbapter;public name : string;public isSupport: boolean;constructor(db:SqlAbapter , name: string, isSupport: boolean){this.db = db;this.name = namethis.isSupport = isSupport}/*** 批量初始化表*/public initDb(tables: Record<string, Record<string, any>>): void{// 验证当前是否开启了离线缓存，验证当前是否支持离线缓存if(!this.isSupport){console.log("当前不支持离线缓存")return;}this.db.open(tables).then((res: boolean) => {if(res){console.log('数据库打开成功')}else {console.log('数据库打开失败')}})}// 验证是否public Db():SqlAbapter{// 验证当前是否开启了离线缓存，验证当前是否支持离线缓存if(!this.isSupport){console.log("当前不支持离线缓存")}return this.db;}
}export default LocalDB;

方法抽象

抽象模版 SqlAbapter.ts

interface SqlAbapter {/*** 数据库是否开启*/isOpen: () => boolean;/*** 开启数据库*/open: (tables: Record<string, Record<string, any>>) => Promise<boolean>;/*** 关闭数据库*/close: () => Promise<boolean>;/*** 是否存在表*/hasTable: (dbTable: string) =>  Promise<boolean>;/*** 创建表*/createTable: (dbTable: string, data: string[]) => Promise<boolean>;/*** 删除表*/dropTable: (dbTable: string) => Promise<boolean>;/*** 新增数据：  indexedDb 重读id会报错*/insertTableData: (dbTable: string, data:Record<string,any>) => Promise<boolean>;/*** 新增或修改*/insertOrReplaceData: (dbTable:string, data:Record<string,any>, condition:Record<string,any>) => Promise<boolean>;/*** 查询数据*/selectTableData: (dbTable:string, condition: Record<string,any>) => Promise<any>;/*** 删除数据*/deleteTableData: (dbTable:string, condition: Record<string,any>) => Promise<boolean>;/*** 更新数据*/updateTableData: (dbTable:string, data: Record<string,any>, condition: Record<string,any>) => Promise<Boolean>;/*** 分页查询*/pullSQL: (dbTable: string, id:string, current: number, size:number) => Promise<any>;}export default SqlAbapter;

sqlite实现

import type SqlAbapter from '@/plugins/db/SqlAbapter'
import { replace, keyValSql, isEmpty, whereSql, updateSetSql } from '@/plugins/utils';
class SqliteAdapter implements SqlAbapter {public dbName: string;public dbPath: string;constructor(dbName: string, dbPath:string){this.dbName = dbName;this.dbPath = dbPath;}// 判断数据库是否打开isOpen() {// 数据库打开了就返回 true,否则返回 falsevar open = plus.sqlite.isOpenDatabase({name: this.dbName,  // 数据库名称path: this.dbPath  // 数据库地址})return open;}// 创建数据库 或 有该数据库就打开open(tables: Record<string, Record<string, any>>):Promise<boolean>  {return new Promise((resolve, reject) => {// 打开数据库plus.sqlite.openDatabase({name: this.dbName,path: this.dbPath,success(e) {resolve(true); // 成功回调// 初始化表 todo: },fail(e) {reject(false);  // 失败回调}})})}hasTable(dbTable: string): Promise<boolean> {let sql = `select * from sqlite_master where type = 'table' and name = '${dbTable}'`return new Promise((resolve, reject) => {// 打开数据库plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(res) {if (res.resultSet.length > 0) {resolve(true); // 成功回调} else {resolve(false);  // 失败回调}},fail(e) {reject(false);  // 失败回调}})})}// 关闭数据库close(): Promise<boolean>  {return new Promise((resolve, reject) => {plus.sqlite.closeDatabase({name: this.dbName,success(e) {resolve(e);},fail(e) {reject(e);}})})}// 数据库建表 sql:'CREATE TABLE IF NOT EXISTS dbTable("id" varchar(50),"name" TEXT) // 创建 CREATE TABLE IF NOT EXISTS 、 dbTable 是表名，不能用数字开头、括号里是表格的表头createTable(dbTable: string, data: string[]): Promise<boolean> {let keys = '';if(!data || data.length <= 0){return new Promise((resolve, reject) => { reject("创建失败,索引不能为空") })}data.forEach((key:string) => {keys = keys + key +",";})keys = replace(keys, ",")// todo: 增加表 属性， varchar等等let sql = `CREATE TABLE IF NOT EXISTS ${dbTable}(${keys})`return new Promise((resolve, reject) => {// executeSql: 执行增删改等操作的SQL语句plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(e) {resolve(true);},fail(e) {reject(false);}})})}// 数据库删表 sql:'DROP TABLE dbTable'dropTable(dbTable: string): Promise<boolean> {return new Promise((resolve, reject) => {plus.sqlite.executeSql({name: this.dbName,sql: [`DROP TABLE ${dbTable}`],success(e) {resolve(true);},fail(e) {reject(false);}})})}// 向表格里添加数据 sql:'INSERT INTO dbTable VALUES('x','x','x')'   对应新增// 或者 sql:'INSERT INTO dbTable ('x','x','x') VALUES('x','x','x')'   具体新增// 插入 INSERT INTO  、 dbTable 是表名、根据表头列名插入列值insertTableData(dbTable: string, data:Record<string,any>): Promise<boolean> {// 判断有没有传参if (dbTable !== undefined && data) {// 判断传的参是否有值if (!isEmpty(data)) {let res = keyValSql(data)// 拼接sql，执行插入var sql = `INSERT INTO ${dbTable} (${res.keySql}) VALUES(${res.valSql})`;// console.log(sql);return new Promise((resolve, reject) => {// 表格添加数据plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(e) {resolve(e);},fail(e) {reject(e);}})})} else {return new Promise((resolve, reject) => { reject("错误添加") })}} else {return new Promise((resolve, reject) => { reject("错误添加") })}}// 根据条件向表格里添加数据  有数据更新、无数据插入// (建表时需要设置主键) 例如 --- "roomid" varchar(50) PRIMARY KEYinsertOrReplaceData(dbTable: string, data: Record<string,any>):Promise<boolean> {// 判断有没有传参if (dbTable !== undefined && data) {if (!isEmpty(data)) {let res = keyValSql(data)let sql = `INSERT OR REPLACE INTO ${dbTable} (${res.keySql}) VALUES(${res.valSql})`;// console.log(sql);return new Promise((resolve, reject) => {// 表格添加数据plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(e) {resolve(e);},fail(e) {reject(e);}})})}else {return new Promise((resolve, reject) => { reject("错误添加") })}} else {return new Promise((resolve, reject) => { reject("错误添加") })}}// 查询获取数据库里的数据 sql:'SELECT * FROM dbTable WHERE lname = 'lvalue''// 查询 SELECT * FROM 、 dbTable 是表名、 WHERE 查找条件 lname,lvalue 是查询条件的列名和列值selectTableData(dbTable:string,  condition: Record<string,any>): Promise<any> {if (dbTable !== undefined) {// 第一个是表单名称，后两个参数是列表名，用来检索let where = ''if(!isEmpty(condition)){where = whereSql(condition)}// if (lname !== undefined && cc !== undefined) {// 	// 两个检索条件// 	var sql = `SELECT * FROM ${dbTable} WHERE ${lname} = '${lvalue}' AND ${cc} = '${dd}'`;// }let sql = `SELECT * FROM ${dbTable}`;if(where){sql = sql + " where " + where;}return new Promise((resolve, reject) => {// 表格查询数据  执行查询的SQL语句plus.sqlite.selectSql({name: this.dbName,sql: sql,success(e) {resolve(e);},fail(e) {reject(e);}})})} else {return new Promise((resolve, reject) => { reject("错误查询") });}}// 删除表里的数据 sql:'DELETE FROM dbTable WHERE lname = 'lvalue''// 删除 DELETE FROM 、 dbTable 是表名、 WHERE 查找条件 lname,lvalue 是查询条件的列名和列值deleteTableData(dbTable:string, condition: Record<string,any>): Promise<boolean> {if (dbTable !== undefined) {let where = ''if(!isEmpty(condition)){where = whereSql(condition)}var sql = `DELETE FROM ${dbTable}`;if(where){sql = sql + " where " + where}return new Promise((resolve, reject) => {// 删除表数据plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(e) {resolve(e);},fail(e) {reject(e);}})})} else {return new Promise((resolve, reject) => { reject("错误删除") });}}// 修改数据表里的数据 sql:"UPDATE dbTable SET 列名 = '列值',列名 = '列值' WHERE lname = 'lvalue'"// 修改 UPDATE 、 dbTable 是表名, data: 要修改的列名=修改后列值, lname,lvalue 是查询条件的列名和列值updateTableData(dbTable:string, data: Record<string,any>, condition: Record<string,any>): Promise<boolean> {if(!dbTable || isEmpty(data)){return new Promise((resolve, reject) => { reject("修改错误") });}let res = updateSetSql(data)var sql = `UPDATE ${dbTable} SET ` + res;if(!isEmpty(condition)){let where = whereSql(condition)if(where){sql = sql + " where " + where}}// WHERE 前面是要修改的列名、列值，后面是条件的列名、列值return new Promise((resolve, reject) => {// 修改表数据plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(e) {resolve(e);},fail(e) {reject(e);}})})}// 获取指定数据条数  sql:"SELECT * FROM dbTable ORDER BY 'id' DESC LIMIT 15 OFFSET 'num'"// dbTable 表名, ORDER BY 代表排序默认正序, id 是排序的条件 DESC 代表倒序，从最后一条数据开始拿// LIMIT 15 OFFSET '${num}',这句的意思是跳过 num 条拿 15 条数据, num 为跳过多少条数据是动态值// 例 初始num设为0，就从最后的数据开始拿15条，下次不拿刚获取的数据，所以可以让num为15，这样就能一步一步的拿完所有的数据pullSQL(dbTable: string, id:string, current: number, size:number): Promise<any> {if(current <= 0){return new Promise((resolve, reject) => { reject("分页查询错误，页码必须从1开始") });}let num = 0;if(current > 0){num = (current - 1) * size}return new Promise((resolve, reject) => {plus.sqlite.selectSql({name: this.dbName,sql: `SELECT * FROM ${dbTable} ORDER BY '${id}' DESC LIMIT ${size} OFFSET '${num}'`,success(e) {resolve(e);},fail(e) {reject(e);}})})}
}export default SqliteAdapter;

indexedDb 实现

import type SqlAbapter from '@/plugins/db/SqlAbapter'
import { keyValSql, isEmpty, whereSql, updateSetSql } from '@/plugins/utils';class IndexDbAdapter implements SqlAbapter {// 这个做法是因为 不同的浏览器获取indexedDB的方式不一样。// mozIndexedDB：火狐浏览器内核；webkitIndexedDB：webkit内核；msIndexedDB：IE内核。public indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB;public dbName: string;public dbPath: string;private request: IDBOpenDBRequest | undefined;private db: IDBDatabase | undefined;constructor(dbName: string, dbPath:string){this.dbName = dbName;this.dbPath = dbPath;// this.request = this.indexedDB.open(this.dbName,1)}// 判断数据库是否打开isOpen() {// 数据库打开了就返回 true,否则返回 falseif(this.request == null){return false;}else {return true;}}// 创建数据库 或 有该数据库就打开open(tables: Record<string, Record<string, any>>):Promise<boolean>  {return new Promise((resolve, reject) => {this.request = this.indexedDB.open(this.dbName,1)let _this = this;this.request.onerror = function(event) {console.error('Database error:', event.target?.errorCode);reject("数据库打开失败");};this.request.onupgradeneeded = function(event) {console.log('onupgradeneeded ====>', event)resolve(true);_this.db =  (event.target as IDBOpenDBRequest).result;// _this.createTable('ttt', ['name', 'val'])if(!isEmpty(tables)){let tabs = Object.keys(tables)tabs.forEach((tab:string) => {_this.hasTable(tab).then((res: boolean) => {if(res){// 当前console.log(`当前数据库: ${tab} 已存在，不进行初始化`)}else {// 初始化表_this.createTable(tab, Object.keys(tables[tab])).then((creRes:any) => {if(creRes){console.log(`当前数据库: ${tab} 初始化完成`)}else {console.log(`当前数据库: ${tab} 初始化失败`)}})}})})}};this.request.onsuccess = function(event) {_this.db = (event.target as IDBOpenDBRequest).result;resolve(true);console.log('Database opened successfully');};})}hasTable(dbTable: string): Promise<boolean> {let _this = this;return new Promise((resolve, reject) => {let res = _this.db?.objectStoreNames.contains(dbTable) as booleanconsole.log('hasTable this.db? =====>', this.db)console.log('hasTable =====>', res)resolve(res);})}// 关闭数据库close(): Promise<boolean>  {let _this = this;return new Promise((resolve, reject) => {_this.db?.close();resolve(true);})}// 数据库建表 sql:'CREATE TABLE IF NOT EXISTS dbTable("id" varchar(50),"name" TEXT) // 创建 CREATE TABLE IF NOT EXISTS 、 dbTable 是表名，不能用数字开头、括号里是表格的表头createTable(dbTable: string, data: string[]): Promise<boolean> {if(!data || data.length <= 0){return new Promise((resolve, reject) => { reject("创建失败,索引不能为空") })}let _this = this;return new Promise((resolve, reject) => {// executeSql: 创建表const objectStore = _this.db?.createObjectStore(dbTable,{ keyPath: 'id' });data.forEach((key:any) => {objectStore?.createIndex(key, key,  {unique: false})})resolve(true)})}// 数据库删表 sql:'DROP TABLE dbTable'dropTable(dbTable: string): Promise<boolean> {return new Promise((resolve, reject) => {reject(false);})}// 向表格里添加数据 sql:'INSERT INTO dbTable VALUES('x','x','x')'   对应新增// 或者 sql:'INSERT INTO dbTable ('x','x','x') VALUES('x','x','x')'   具体新增// 插入 INSERT INTO  、 dbTable 是表名、根据表头列名插入列值insertTableData(dbTable: string, data:Record<string,any>): Promise<boolean> {// 判断有没有传参if (dbTable !== undefined && data) {// 判断传的参是否有值if (!isEmpty(data)) {let _this = this;return new Promise((resolve, reject) => {// 添加数据到对象存储空间let transaction = _this.db?.transaction([dbTable], 'readwrite');const objectStore = transaction?.objectStore(dbTable);let request = objectStore?.add(data) as IDBRequest;// 写入数据的事件监听request.onsuccess = function (event) {resolve(true)console.log('数据写入成功');};request.onerror = function (event) {reject("数据写入失败: " + event?.target?.error?.message)console.log('数据写入失败： event =====》 ', event);}})} else {return new Promise((resolve, reject) => { reject("错误添加") })}} else {return new Promise((resolve, reject) => { reject("错误添加") })}}// 根据条件向表格里添加数据  有数据更新、无数据插入// (建表时需要设置主键) 例如 --- "roomid" varchar(50) PRIMARY KEYinsertOrReplaceData(dbTable: string, data: Record<string,any>):Promise<boolean> {// 判断有没有传参if (dbTable !== undefined && data) {if (!isEmpty(data)) {return new Promise((resolve, reject) => {// 表格添加数据reject(false);})}else {return new Promise((resolve, reject) => { reject("错误添加") })}} else {return new Promise((resolve, reject) => { reject("错误添加") })}}// 查询获取数据库里的数据 sql:'SELECT * FROM dbTable WHERE lname = 'lvalue''// 查询 SELECT * FROM 、 dbTable 是表名、 WHERE 查找条件 lname,lvalue 是查询条件的列名和列值selectTableData(dbTable:string,  condition: Record<string,any>): Promise<any> {if (dbTable !== undefined) {// 第一个是表单名称，后两个参数是列表名，用来检索return new Promise((resolve, reject) => {reject(false);})} else {return new Promise((resolve, reject) => { reject("错误查询") });}}// 删除表里的数据 sql:'DELETE FROM dbTable WHERE lname = 'lvalue''// 删除 DELETE FROM 、 dbTable 是表名、 WHERE 查找条件 lname,lvalue 是查询条件的列名和列值deleteTableData(dbTable:string, condition: Record<string,any>): Promise<boolean> {if (dbTable !== undefined) {return new Promise((resolve, reject) => {reject(false);})} else {return new Promise((resolve, reject) => { reject("错误删除") });}}// 修改数据表里的数据 sql:"UPDATE dbTable SET 列名 = '列值',列名 = '列值' WHERE lname = 'lvalue'"// 修改 UPDATE 、 dbTable 是表名, data: 要修改的列名=修改后列值, lname,lvalue 是查询条件的列名和列值updateTableData(dbTable:string, data: Record<string,any>, condition: Record<string,any>): Promise<boolean> {return new Promise((resolve, reject) => {reject(false);})}// 获取指定数据条数  sql:"SELECT * FROM dbTable ORDER BY 'id' DESC LIMIT 15 OFFSET 'num'"// dbTable 表名, ORDER BY 代表排序默认正序, id 是排序的条件 DESC 代表倒序，从最后一条数据开始拿// LIMIT 15 OFFSET '${num}',这句的意思是跳过 num 条拿 15 条数据, num 为跳过多少条数据是动态值// 例 初始num设为0，就从最后的数据开始拿15条，下次不拿刚获取的数据，所以可以让num为15，这样就能一步一步的拿完所有的数据pullSQL(dbTable: string, id:string, current: number, size:number): Promise<any> {return new Promise((resolve, reject) => {reject(false);})}
}export default IndexDbAdapter;

动态选取

db-plugins

import SqliteAdapter from './db/sqlite/sqliteAdapter';
import IndexDbAdapter from './db/indexedDb/indexedDbAdapter';
import { DbConfig, tableConfig } from '@/enums/DbEnums'
import  LocalDB from '@/class/DbClass'let localDB : LocalDB;
// #ifdef APP-PLUS
//  App 环境使用 sqlite 适配器localDB = new LocalDB(new SqliteAdapter(DbConfig.Name, DbConfig.Path), 'sqlite', true);
// #endif
// #ifdef  MP-WEIXIN
// 小程序环境使用内存适配器,自定义实现// #endif
// #ifdef H5
//  浏览器 环境使用 indexeddb 适配器localDB = new LocalDB(new IndexDbAdapter(DbConfig.Name, DbConfig.Path), 'indexedDb', true);
// #endifconsole.log('当前环境注册的本地数据库为',localDB.name)// 初始化表
localDB.initDb(tableConfig)
export default localDB;

api应用

testService

import {request , CallBackFunType} from '@/utils/request'
import { HttpPath } from '@/enums/constant'
import localDB from '@/plugins/db-plugins'
import type LocalDB from '@/class/DbClass'
import { DbTable, DbConfig } from '@/enums/DbEnums'
import BaseApi from '@/class/baseApiClass'class TestApi extends BaseApi{constructor(table: string, localDB:LocalDB){super(table, localDB)}public save(data: {id: string ,name: string, value: string}) {return request({'url': HttpPath.App + '/dict/type','method': 'post',data}, async (requestConfig: any) => {console.log('离线回调操作: ', requestConfig)const res = await this.verifyTable(true);return new Promise<CallBackFunType<any>>((resolve, reject) => {if(res.code != 200){reject(res)}else{// 执行数据库操作this.localDB.Db().insertTableData(DbTable.Test, data).then((res) => {if(res){resolve(new CallBackFunType({}).success())}else {reject(new CallBackFunType({}).fail())}}).catch((e:any) => {reject(e)})}})})}
}export default new TestApi(DbTable.Test, localDB);

页面使用

<template><view>测试</view>
</template><script lang="ts" setup>import { onLoad } from '@dcloudio/uni-app';import TestApi from '@/api/testService'onLoad(() => {TestApi.save({id:'1231',name: '2321', value: 'dasdas'}).then((res:any) => {console.log(res)})})
</script><style lang="scss">
</style>

执行效果 以浏览器(indexedDb)为例