331 lines
9.4 KiB
JavaScript
331 lines
9.4 KiB
JavaScript
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/**
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*
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* @param {*} dbName 数据库名称
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* @param {*} version 数据库的版本
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*/
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function openDB(dbName, version = 1) {
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return new Promise((resolve, reject) => {
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var db; // 存储数据库对象
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// 打开数据库，如果没有就是创建操作
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var request = indexedDB.open(dbName, version);
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// 数据库打开或者创建成功的时候
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request.onsuccess = function (event) {
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db = event.target.result;
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console.log("数据库打开成功");
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resolve(db);
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}
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// 打开失败
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request.onerror = function () {
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console.log("数据库打开失败");
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}
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// 数据库发生更新的时候
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// 1. 版本号更新 2. 添加或者删除了表（对象仓库）的时候
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// 当我们第一次调用 open 方法时，会触发这个事件
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// 我们在这里来初始化我们的表
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request.onupgradeneeded = function (event) {
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console.log("数据库版本更新");
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db = event.target.result;
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// 创建数据仓库（表）
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var objectStore = db.createObjectStore("stu", {
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keyPath: "stuId", // 这是主键
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autoIncrement: true // 实现自增
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});
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// 创建索引，有了索引之后，查询速度大大增快（类比新华字典）
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objectStore.createIndex("stuId", "stuId", { unique: true });
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objectStore.createIndex("stuName", "stuName", { unique: false });
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objectStore.createIndex("stuAge", "stuAge", { unique: false });
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}
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})
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}
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/**
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* 关闭数据库
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* @param {object} db 数据库实例
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*/
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function closeDB(db) {
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db.close();
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console.log("数据库已关闭");
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}
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/**
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* 删除数据库
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* @param {object} dbName 数据库名称
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*/
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function deleteDBAll(dbName) {
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console.log(dbName);
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let deleteRequest = window.indexedDB.deleteDatabase(dbName);
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deleteRequest.onerror = function (event) {
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console.log("删除失败");
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};
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deleteRequest.onsuccess = function (event) {
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console.log("删除成功");
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};
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}
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/**
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*
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* @param {*} db 数据库实例
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* @param {*} storeName 数据仓库实例（表）
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* @param {*} data 要添加的数据
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*/
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function addData(db, storeName, data) {
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var request = db.transaction([storeName], "readwrite")
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.objectStore(storeName)
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.add(data);
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request.onsuccess = function () {
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console.log("数据写入成功");
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}
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request.onerror = function () {
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console.log("数据写入失败")
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}
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}
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/**
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* 通过主键来读取数据
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* @param {*} db 数据库实例对象
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* @param {*} storeName 数据仓库（表）实例对象
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* @param {*} key 主键
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*/
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function getDataByKey(db, storeName, key) {
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return new Promise((resolve, reject) => {
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var request = db.transaction([storeName])
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.objectStore(storeName)
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.get(key);
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request.onsuccess = function () {
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resolve(request.result)
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}
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request.onerror = function () {
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console.log("数据查询失败");
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}
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})
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}
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/**
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* 通过主键来读取数据
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* @param {*} db 数据库实例对象
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* @param {*} storeName 数据仓库（表）实例对象
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*/
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function getAllData(db, storeName) {
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return new Promise((resolve, reject) => {
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var request = db.transaction([storeName])
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.objectStore(storeName)
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.getAll();
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request.onsuccess = function () {
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resolve(request.result)
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}
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request.onerror = function () {
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console.log("数据查询失败");
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}
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})
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}
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/**
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* 通过游标（指针）来查询所有的数据
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* @param {*} db
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* @param {*} storeName
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*/
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function cursorGetData(db, storeName) {
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return new Promise((resolve, reject) => {
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var list = []; // 用于存放所有的数据
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var request = db.transaction([storeName], "readwrite")
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.objectStore(storeName)
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.openCursor(); // 创建一个指针（游标）
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request.onsuccess = function (event) {
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var cursor = event.target.result;
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// 查看游标（指针）有没有返回一条数据
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if (cursor) {
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list.push(cursor.value);
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cursor.continue(); // 移动到下一条数据
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} else {
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resolve(list)
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}
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}
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})
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}
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/**
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* 根据索引来查询数据（只会返回一条）
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* @param {*} db
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* @param {*} storeName
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* @param {*} indexName 索引名称
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* @param {*} indexValue 索引值
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*/
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function getDataByIndex(db, storeName, indexName, indexValue) {
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return new Promise((resolve, reject) => {
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var request = db.transaction([storeName], "readwrite")
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.objectStore(storeName)
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.index(indexName)
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.get(indexValue);
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request.onsuccess = function (event) {
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resolve(event.target.result);
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}
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})
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}
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/**
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* 根据索引和游标来查询数据
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* @param {*} db
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* @param {*} storeName
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* @param {*} indexName 索引名称
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* @param {*} indexValue 索引值
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*/
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function getDataByIndex(db, storeName, indexName, indexValue) {
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return new Promise((resolve, reject) => {
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var list = []; // 存储所有满足条件的数据
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var request = db.transaction([storeName], "readwrite")
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.objectStore(storeName)
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.index(indexName)
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.openCursor(IDBKeyRange.lowerBound(indexValue));
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request.onsuccess = function (event) {
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var cursor = event.target.result;
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if (cursor) {
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list.push(cursor.value);
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cursor.continue();
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} else {
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resolve(list);
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}
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}
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})
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}
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/**
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* 通过索引和游标分页查询记录
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* @param {object} db 数据库实例
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* @param {string} storeName 仓库名称
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* @param {string} indexName 索引名称
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* @param {string} indexValue 索引值
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* @param {number} page 页码
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* @param {number} pageSize 查询条数
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*/
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function cursorGetDataByIndexAndPage(
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db,
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storeName,
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indexName,
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indexValue,
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page,
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pageSize
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) {
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return new Promise((resolve, reject) => {
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var list = []; // 用于存储当前页的分页数据
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var counter = 0; // 创建一个计数器
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var isPass = true; // 是否要跳过数据
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var request = db.transaction([storeName], "readwrite")
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.objectStore(storeName)
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.openCursor(); // 创建一个指针（游标）对象（目前是指向第一条数据）
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request.onsuccess = function (event) {
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var cursor = event.target.result;
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// 接下来有一个很重要的判断，判断是否要跳过一些数据
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if (page > 1 && isPass) {
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isPass = false;
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cursor.advance((page - 1) * pageSize); // 跳过数据
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return;
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}
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if (cursor) {
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list.push(cursor.value);
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counter++;
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if (counter < pageSize) {
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cursor.continue();
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} else {
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cursor = null;
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resolve(list);
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}
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} else {
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resolve(list)
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}
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}
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})
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}
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/**
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* 更新数据
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* @param {object} db 数据库实例
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* @param {string} storeName 仓库名称
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* @param {object} data 数据
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*/
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function updateDB(db, storeName, data) {
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return new Promise((resolve, reject) => {
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var request = db.transaction([storeName], "readwrite")
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.objectStore(storeName)
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.put(data);
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request.onsuccess = function () {
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resolve({
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status: true,
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message: "更新数据成功"
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})
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}
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})
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}
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/**
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* 通过主键删除数据
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* @param {object} db 数据库实例
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* @param {string} storeName 仓库名称
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* @param {object} id 主键值
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*/
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function deleteDB(db, storeName, id) {
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return new Promise((resolve, reject) => {
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var request = db
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.transaction([storeName], "readwrite")
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.objectStore(storeName)
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.delete(id);
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request.onsuccess = function () {
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resolve({
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status: true,
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message: "删除数据成功"
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})
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};
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request.onerror = function () {
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reject({
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status: true,
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message: "删除数据失败"
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})
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};
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})
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}
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/**
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* 通过索引和游标删除指定的数据
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* @param {object} db 数据库实例
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* @param {string} storeName 仓库名称
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* @param {string} indexName 索引名
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* @param {object} indexValue 索引值
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*/
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function cursorDelete(db, storeName, indexName, indexValue) {
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return new Promise((resolve, reject)=>{
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var request = db.transaction([storeName], "readwrite")
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.objectStore(storeName)
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.index(indexName)
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.openCursor(IDBKeyRange.only(indexValue));
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request.onsuccess = function(event){
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var cursor = event.target.result;
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if(cursor){
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var deleteRequest = cursor.delete();
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deleteRequest.onsuccess = function(){
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resolve({
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status: true,
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message: "删除数据成功"
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})
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}
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cursor.continue();
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}
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}
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})
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}
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