js操作indexedDB增删改查示例

js操作indexedDB增删改查示例

if ('indexedDB' in window) {
    // 如果数据库不存在则创建，如果存在但是version更大，会自动升级不会复制原来的版本
    var req = indexedDB.open("TestDB", 1);

    req.onupgradeneeded = function(e) {
        var db = req.result;
        // var store = db.createObjectStore("student", {autoIncrement: true}); 使用自增键
        // 创建student表
        var store = db.createObjectStore("student", {keyPath: 'id'});
        // 设置id为主键
        store.createIndex('student_id_unqiue','id', {unique: true});
    }

    req.onsuccess = function(event) {
        var students = [
            {id: 1, name: '小叶', age: '11'},
            {id: 2, name: '小王', age: '12'},
            {id: 3, name: '小张', age: '13'}
        ];

        var db = event.target.result;
        // var transaction = db.transaction('student', 'readwrite');
        var transaction = db.transaction(['student'], 'readwrite');
        transaction.onsuccess = function(event) {
            console.log('[Transaction] 好了!');
        };

        var studentsStore = transaction.objectStore('student');
        students.forEach(function(student){
            var db_op_req = studentsStore.add(student);
            db_op_req.onsuccess = function() {
                console.log("存好了");
            }
        });

        studentsStore.count().onsuccess = function(event) {
            console.log('学生个数', event.target.result);
        };

        // 获取id为1的学生
        studentsStore.get(1).onsuccess = function(event) {
            console.log('id为1的学生', event.target.result);
        };

        // 更新id为1的学生
        students[0].name = '小小叶';
        studentsStore.put(students[0]).onsuccess = function(event) {
            console.log('更新id为1的学生姓名', event.target.result);
        };

        // 删除id为2的学生
        studentsStore.delete(2).onsuccess = function(event) {
            console.log('id为2的学生已经删除');
        };
    }

    req.onerror = function() {
        console.log("数据库出错");
    }
}else{
    console.log('你的浏览器不支持IndexedDB');
}