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  • IndexedDb基本使用

    打开控制台,下面按钮,在谷歌浏览器,开发者工具的application中的IndexedDB查看数据库表和数据。

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Document</title>
    
        <script>
            // indexeddb
            // https://wangdoc.com/javascript/bom/indexeddb.html#indexeddb-对象
            var dbName = 'patrolLine';
            var dbVersion = 1;
            var db;
            // 打开数据库
            function openIDB(params) {
                params = params || {};
                /**
                 * 第一个参数是字符串,表示数据库的名字。
                 * 如果指定的数据库不存在,就会新建数据库。
                 * 
                 * 第二个参数是整数,表示数据库的版本。
                 * 如果省略,打开已有数据库时,默认为当前版本;新建数据库时,默认为1
                 */
                var request = window.indexedDB.open(dbName, dbVersion);
                // 成功打开数据库
                request.onsuccess = function (event) {
                    db = request.result;
                    console.log('数据库打开成功');
                    params.onsuccess && params.onsuccess(event)
                };
                // 数据库升级事件
                request.onupgradeneeded = function (event) {
                    db = event.target.result;
                    params.onupgradeneeded && params.onupgradeneeded(event)
    
                    var objectStore;
                    if (!db.objectStoreNames.contains('violationrecords')) {
                        objectStore = db.createObjectStore('violationrecords', { keyPath: 'id', autoIncrement: true });
                        // 建立索引
                        // objectStore.createIndex('name', 'name', { unique: false });
                    }
                }
                // 打开数据库失败
                request.onerror = function (event) {
                    console.log('数据库打开报错');
                    params.onerror && params.onerror(event)
                };
            }
            // 关闭数据库
            function closeIDB() {
                db.close();
                db = null;
            }
    
            function removeIDB() {
                var request = window.indexedDB.deleteDatabase(dbName);
                request.onerror = function (event) {
                    console.log('数据库删除失败');
                };
    
                request.onsuccess = function (event) {
                    console.log('数据库删除成功');
                };
            }
    
            function add() {
                var request = db.transaction(['violationrecords'], 'readwrite')
                    .objectStore('violationrecords')
                    .add({ name: '张三', age: 24, email: 'zhangsan@example.com' });
    
                request.onsuccess = function (event) {
                    console.log('数据写入成功');
                };
    
                request.onerror = function (event) {
                    console.log('数据写入失败');
                }
            }
            // 索引查询
            function readByIndex() {
                var transaction = db.transaction(['person'], 'readonly');
                var store = transaction.objectStore('person');
                var index = store.index('name');
                var request = index.get('李四');
    
                request.onsuccess = function (e) {
                    var result = e.target.result;
                    if (result) {
                        // ...
                    } else {
                        // ...
                    }
                }
            }
            // id查询
            function read() {
                var transaction = db.transaction(['violationrecords']);
                var objectStore = transaction.objectStore('violationrecords');
                var request = objectStore.get(1);
    
                request.onerror = function(event) {
                    console.log('事务失败');
                };
    
                request.onsuccess = function( event) {
                    if (request.result) {
                        console.log('Name: ' + request.result.name);
                        console.log('Age: ' + request.result.age);
                        console.log('Email: ' + request.result.email);
                    } else {
                        console.log('未获得数据记录');
                    }
                };
            }
            // 游标查询所有
            function readAll() {
                var objectStore = db.transaction('violationrecords').objectStore('violationrecords');
    
                objectStore.openCursor().onsuccess = function (event) {
                    var cursor = event.target.result;
    
                    if (cursor) {
                        console.log('Id: ' + cursor.key);
                        console.log('Name: ' + cursor.value.name);
                        console.log('Age: ' + cursor.value.age);
                        console.log('Email: ' + cursor.value.email);
                        cursor.continue();
                    } else {
                        console.log('没有更多数据了!');
                    }
                };
            }
            // 更新
            function update() {
                var request = db.transaction(['violationrecords'], 'readwrite')
                    .objectStore('violationrecords')
                    .put({ id: 1, name: '李四', age: 35, email: 'lisi@example.com' });
    
                request.onsuccess = function (event) {
                    console.log('数据更新成功');
                };
    
                request.onerror = function (event) {
                    console.log('数据更新失败');
                }
            }
            // 删除
            function remove() {
                var request = db.transaction(['violationrecords'], 'readwrite')
                    .objectStore('violationrecords')
                    .delete(1);
    
                request.onsuccess = function (event) {
                    console.log('数据删除成功');
                };
            }
    
        </script>
    </head>
    <body>
        <button type="button" onclick="openIDB()">打开数据库</button>
        <button type="button" onclick="removeIDB()">删除数据库</button>
        <button type="button" onclick="add()">插入</button>
        <button type="button" onclick="readAll()">查询</button>
        <button type="button" onclick="update()">更新</button>
        <button type="button" onclick="remove()">删除</button>
    </body>
    </html>
    

     推荐使用的插件如下,个人使用了觉得还行。

    https://jsstore.net/tutorial/get-started/

    https://github.com/ujjwalguptaofficial/JsStore

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  • 原文地址:https://www.cnblogs.com/guxingzhe/p/13213615.html
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