項目有個需求,需要生成app和小程序,app支持離線數據庫,如果當前沒有網絡提醒用戶開啟離線模式,所以就隨便搞了下,具體的思路就是: 一個接口和多個實現類(類似后端的模板設計模式),例如sqlite實現類,indexedDB實現類等等,根據環境動態選用具體的實現類
indexedDB有些方法沒有改,sqlite沒有測試,此處就是提供一個思路,只是用來學習和研究著玩了
目錄
class類
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("構造初始化失敗, table: " + this.table)})}}public getTable(): string{return this.table;}public getHasTable(): boolean{return this.hasTable;}public setHasTable(hasTable:boolean){this.hasTable = hasTable;}/*** 驗證是否存在表信息*/public async verifyTable(init: boolean = false): Promise<CallBackFunType<any>>{if(!this.getHasTable() && init){const res = await this.init();if(!res){return new CallBackFunType({}).fail('初始化數據庫失敗')}else {return new CallBackFunType({}).success('初始化數據庫成功');}}return new CallBackFunType({}).success('存在數據庫');}/*** 初始化*/public async init(): Promise<boolean>{// 瀏覽器不能直接新建,需要適配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'// 根據平臺選擇適配器
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{// 驗證當前是否開啟了離線緩存,驗證當前是否支持離線緩存if(!this.isSupport){console.log("當前不支持離線緩存")return;}this.db.open(tables).then((res: boolean) => {if(res){console.log('數據庫打開成功')}else {console.log('數據庫打開失敗')}})}// 驗證是否public Db():SqlAbapter{// 驗證當前是否開啟了離線緩存,驗證當前是否支持離線緩存if(!this.isSupport){console.log("當前不支持離線緩存")}return this.db;}
}export default LocalDB;
方法抽象
抽象模版 SqlAbapter.ts
interface SqlAbapter {/*** 數據庫是否開啟*/isOpen: () => boolean;/*** 開啟數據庫*/open: (tables: Record<string, Record<string, any>>) => Promise<boolean>;/*** 關閉數據庫*/close: () => Promise<boolean>;/*** 是否存在表*/hasTable: (dbTable: string) => Promise<boolean>;/*** 創建表*/createTable: (dbTable: string, data: string[]) => Promise<boolean>;/*** 刪除表*/dropTable: (dbTable: string) => Promise<boolean>;/*** 新增數據: indexedDb 重讀id會報錯*/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>;/*** 查詢數據*/selectTableData: (dbTable:string, condition: Record<string,any>) => Promise<any>;/*** 刪除數據*/deleteTableData: (dbTable:string, condition: Record<string,any>) => Promise<boolean>;/*** 更新數據*/updateTableData: (dbTable:string, data: Record<string,any>, condition: Record<string,any>) => Promise<Boolean>;/*** 分頁查詢*/pullSQL: (dbTable: string, id:string, current: number, size:number) => Promise<any>;}export default SqlAbapter;
sqlite實現
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;}// 判斷數據庫是否打開isOpen() {// 數據庫打開了就返回 true,否則返回 falsevar open = plus.sqlite.isOpenDatabase({name: this.dbName, // 數據庫名稱path: this.dbPath // 數據庫地址})return open;}// 創建數據庫 或 有該數據庫就打開open(tables: Record<string, Record<string, any>>):Promise<boolean> {return new Promise((resolve, reject) => {// 打開數據庫plus.sqlite.openDatabase({name: this.dbName,path: this.dbPath,success(e) {resolve(true); // 成功回調// 初始化表 todo: },fail(e) {reject(false); // 失敗回調}})})}hasTable(dbTable: string): Promise<boolean> {let sql = `select * from sqlite_master where type = 'table' and name = '${dbTable}'`return new Promise((resolve, reject) => {// 打開數據庫plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(res) {if (res.resultSet.length > 0) {resolve(true); // 成功回調} else {resolve(false); // 失敗回調}},fail(e) {reject(false); // 失敗回調}})})}// 關閉數據庫close(): Promise<boolean> {return new Promise((resolve, reject) => {plus.sqlite.closeDatabase({name: this.dbName,success(e) {resolve(e);},fail(e) {reject(e);}})})}// 數據庫建表 sql:'CREATE TABLE IF NOT EXISTS dbTable("id" varchar(50),"name" TEXT) // 創建 CREATE TABLE IF NOT EXISTS 、 dbTable 是表名,不能用數字開頭、括號里是表格的表頭createTable(dbTable: string, data: string[]): Promise<boolean> {let keys = '';if(!data || data.length <= 0){return new Promise((resolve, reject) => { reject("創建失敗,索引不能為空") })}data.forEach((key:string) => {keys = keys + key +",";})keys = replace(keys, ",")// todo: 增加表 屬性, varchar等等let sql = `CREATE TABLE IF NOT EXISTS ${dbTable}(${keys})`return new Promise((resolve, reject) => {// executeSql: 執行增刪改等操作的SQL語句plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(e) {resolve(true);},fail(e) {reject(false);}})})}// 數據庫刪表 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);}})})}// 向表格里添加數據 sql:'INSERT INTO dbTable VALUES('x','x','x')' 對應新增// 或者 sql:'INSERT INTO dbTable ('x','x','x') VALUES('x','x','x')' 具體新增// 插入 INSERT INTO 、 dbTable 是表名、根據表頭列名插入列值insertTableData(dbTable: string, data:Record<string,any>): Promise<boolean> {// 判斷有沒有傳參if (dbTable !== undefined && data) {// 判斷傳的參是否有值if (!isEmpty(data)) {let res = keyValSql(data)// 拼接sql,執行插入var sql = `INSERT INTO ${dbTable} (${res.keySql}) VALUES(${res.valSql})`;// console.log(sql);return new Promise((resolve, reject) => {// 表格添加數據plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(e) {resolve(e);},fail(e) {reject(e);}})})} else {return new Promise((resolve, reject) => { reject("錯誤添加") })}} else {return new Promise((resolve, reject) => { reject("錯誤添加") })}}// 根據條件向表格里添加數據 有數據更新、無數據插入// (建表時需要設置主鍵) 例如 --- "roomid" varchar(50) PRIMARY KEYinsertOrReplaceData(dbTable: string, data: Record<string,any>):Promise<boolean> {// 判斷有沒有傳參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) => {// 表格添加數據plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(e) {resolve(e);},fail(e) {reject(e);}})})}else {return new Promise((resolve, reject) => { reject("錯誤添加") })}} else {return new Promise((resolve, reject) => { reject("錯誤添加") })}}// 查詢獲取數據庫里的數據 sql:'SELECT * FROM dbTable WHERE lname = 'lvalue''// 查詢 SELECT * FROM 、 dbTable 是表名、 WHERE 查找條件 lname,lvalue 是查詢條件的列名和列值selectTableData(dbTable:string, condition: Record<string,any>): Promise<any> {if (dbTable !== undefined) {// 第一個是表單名稱,后兩個參數是列表名,用來檢索let where = ''if(!isEmpty(condition)){where = whereSql(condition)}// if (lname !== undefined && cc !== undefined) {// // 兩個檢索條件// 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) => {// 表格查詢數據 執行查詢的SQL語句plus.sqlite.selectSql({name: this.dbName,sql: sql,success(e) {resolve(e);},fail(e) {reject(e);}})})} else {return new Promise((resolve, reject) => { reject("錯誤查詢") });}}// 刪除表里的數據 sql:'DELETE FROM dbTable WHERE lname = 'lvalue''// 刪除 DELETE FROM 、 dbTable 是表名、 WHERE 查找條件 lname,lvalue 是查詢條件的列名和列值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) => {// 刪除表數據plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(e) {resolve(e);},fail(e) {reject(e);}})})} else {return new Promise((resolve, reject) => { reject("錯誤刪除") });}}// 修改數據表里的數據 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 是查詢條件的列名和列值updateTableData(dbTable:string, data: Record<string,any>, condition: Record<string,any>): Promise<boolean> {if(!dbTable || isEmpty(data)){return new Promise((resolve, reject) => { reject("修改錯誤") });}let res = updateSetSql(data)var sql = `UPDATE ${dbTable} SET ` + res;if(!isEmpty(condition)){let where = whereSql(condition)if(where){sql = sql + " where " + where}}// WHERE 前面是要修改的列名、列值,后面是條件的列名、列值return new Promise((resolve, reject) => {// 修改表數據plus.sqlite.executeSql({name: this.dbName,sql: [sql],success(e) {resolve(e);},fail(e) {reject(e);}})})}// 獲取指定數據條數 sql:"SELECT * FROM dbTable ORDER BY 'id' DESC LIMIT 15 OFFSET 'num'"// dbTable 表名, ORDER BY 代表排序默認正序, id 是排序的條件 DESC 代表倒序,從最后一條數據開始拿// LIMIT 15 OFFSET '${num}',這句的意思是跳過 num 條拿 15 條數據, num 為跳過多少條數據是動態值// 例 初始num設為0,就從最后的數據開始拿15條,下次不拿剛獲取的數據,所以可以讓num為15,這樣就能一步一步的拿完所有的數據pullSQL(dbTable: string, id:string, current: number, size:number): Promise<any> {if(current <= 0){return new Promise((resolve, reject) => { reject("分頁查詢錯誤,頁碼必須從1開始") });}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 實現
import type SqlAbapter from '@/plugins/db/SqlAbapter'
import { keyValSql, isEmpty, whereSql, updateSetSql } from '@/plugins/utils';class IndexDbAdapter implements SqlAbapter {// 這個做法是因為 不同的瀏覽器獲取indexedDB的方式不一樣。// mozIndexedDB:火狐瀏覽器內核;webkitIndexedDB:webkit內核;msIndexedDB:IE內核。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)}// 判斷數據庫是否打開isOpen() {// 數據庫打開了就返回 true,否則返回 falseif(this.request == null){return false;}else {return true;}}// 創建數據庫 或 有該數據庫就打開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("數據庫打開失敗");};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){// 當前console.log(`當前數據庫: ${tab} 已存在,不進行初始化`)}else {// 初始化表_this.createTable(tab, Object.keys(tables[tab])).then((creRes:any) => {if(creRes){console.log(`當前數據庫: ${tab} 初始化完成`)}else {console.log(`當前數據庫: ${tab} 初始化失敗`)}})}})})}};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);})}// 關閉數據庫close(): Promise<boolean> {let _this = this;return new Promise((resolve, reject) => {_this.db?.close();resolve(true);})}// 數據庫建表 sql:'CREATE TABLE IF NOT EXISTS dbTable("id" varchar(50),"name" TEXT) // 創建 CREATE TABLE IF NOT EXISTS 、 dbTable 是表名,不能用數字開頭、括號里是表格的表頭createTable(dbTable: string, data: string[]): Promise<boolean> {if(!data || data.length <= 0){return new Promise((resolve, reject) => { reject("創建失敗,索引不能為空") })}let _this = this;return new Promise((resolve, reject) => {// executeSql: 創建表const objectStore = _this.db?.createObjectStore(dbTable,{ keyPath: 'id' });data.forEach((key:any) => {objectStore?.createIndex(key, key, {unique: false})})resolve(true)})}// 數據庫刪表 sql:'DROP TABLE dbTable'dropTable(dbTable: string): Promise<boolean> {return new Promise((resolve, reject) => {reject(false);})}// 向表格里添加數據 sql:'INSERT INTO dbTable VALUES('x','x','x')' 對應新增// 或者 sql:'INSERT INTO dbTable ('x','x','x') VALUES('x','x','x')' 具體新增// 插入 INSERT INTO 、 dbTable 是表名、根據表頭列名插入列值insertTableData(dbTable: string, data:Record<string,any>): Promise<boolean> {// 判斷有沒有傳參if (dbTable !== undefined && data) {// 判斷傳的參是否有值if (!isEmpty(data)) {let _this = this;return new Promise((resolve, reject) => {// 添加數據到對象存儲空間let transaction = _this.db?.transaction([dbTable], 'readwrite');const objectStore = transaction?.objectStore(dbTable);let request = objectStore?.add(data) as IDBRequest;// 寫入數據的事件監聽request.onsuccess = function (event) {resolve(true)console.log('數據寫入成功');};request.onerror = function (event) {reject("數據寫入失敗: " + event?.target?.error?.message)console.log('數據寫入失敗: event =====》 ', event);}})} else {return new Promise((resolve, reject) => { reject("錯誤添加") })}} else {return new Promise((resolve, reject) => { reject("錯誤添加") })}}// 根據條件向表格里添加數據 有數據更新、無數據插入// (建表時需要設置主鍵) 例如 --- "roomid" varchar(50) PRIMARY KEYinsertOrReplaceData(dbTable: string, data: Record<string,any>):Promise<boolean> {// 判斷有沒有傳參if (dbTable !== undefined && data) {if (!isEmpty(data)) {return new Promise((resolve, reject) => {// 表格添加數據reject(false);})}else {return new Promise((resolve, reject) => { reject("錯誤添加") })}} else {return new Promise((resolve, reject) => { reject("錯誤添加") })}}// 查詢獲取數據庫里的數據 sql:'SELECT * FROM dbTable WHERE lname = 'lvalue''// 查詢 SELECT * FROM 、 dbTable 是表名、 WHERE 查找條件 lname,lvalue 是查詢條件的列名和列值selectTableData(dbTable:string, condition: Record<string,any>): Promise<any> {if (dbTable !== undefined) {// 第一個是表單名稱,后兩個參數是列表名,用來檢索return new Promise((resolve, reject) => {reject(false);})} else {return new Promise((resolve, reject) => { reject("錯誤查詢") });}}// 刪除表里的數據 sql:'DELETE FROM dbTable WHERE lname = 'lvalue''// 刪除 DELETE FROM 、 dbTable 是表名、 WHERE 查找條件 lname,lvalue 是查詢條件的列名和列值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("錯誤刪除") });}}// 修改數據表里的數據 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 是查詢條件的列名和列值updateTableData(dbTable:string, data: Record<string,any>, condition: Record<string,any>): Promise<boolean> {return new Promise((resolve, reject) => {reject(false);})}// 獲取指定數據條數 sql:"SELECT * FROM dbTable ORDER BY 'id' DESC LIMIT 15 OFFSET 'num'"// dbTable 表名, ORDER BY 代表排序默認正序, id 是排序的條件 DESC 代表倒序,從最后一條數據開始拿// LIMIT 15 OFFSET '${num}',這句的意思是跳過 num 條拿 15 條數據, num 為跳過多少條數據是動態值// 例 初始num設為0,就從最后的數據開始拿15條,下次不拿剛獲取的數據,所以可以讓num為15,這樣就能一步一步的拿完所有的數據pullSQL(dbTable: string, id:string, current: number, size:number): Promise<any> {return new Promise((resolve, reject) => {reject(false);})}
}export default IndexDbAdapter;
動態選取
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 環境使用 sqlite 適配器localDB = new LocalDB(new SqliteAdapter(DbConfig.Name, DbConfig.Path), 'sqlite', true);
// #endif
// #ifdef MP-WEIXIN
// 小程序環境使用內存適配器,自定義實現// #endif
// #ifdef H5
// 瀏覽器 環境使用 indexeddb 適配器localDB = new LocalDB(new IndexDbAdapter(DbConfig.Name, DbConfig.Path), 'indexedDb', true);
// #endifconsole.log('當前環境注冊的本地數據庫為',localDB.name)// 初始化表
localDB.initDb(tableConfig)
export default localDB;
api應用
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('離線回調操作: ', requestConfig)const res = await this.verifyTable(true);return new Promise<CallBackFunType<any>>((resolve, reject) => {if(res.code != 200){reject(res)}else{// 執行數據庫操作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);
頁面使用
<template><view>測試</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>
執行效果 以瀏覽器(indexedDb)為例