var students = [{

    id: 1001,

    name: "Byron",

    age: 24

}, {

    id: 1002,

    name: "Frank",

    age: 30

}, {

    id: 1003,

    name: "Aaron",

    age: 26

}, {

    id: 1004,

    name: "Casper",

    age: 26

}];

function hasIndexedDB() {

    if ("indexedDB" in window) {

        console.log("支持indexedDB!");

        return true;

    } else {

        console.log("不支持indexedDB!");

        return false;

    }

}

var dataBase = null;

// 打开数据库

function openIDB(IDBName, IDBVersion) {

    var IDBVersion = IDBVersion || 1;

    var IDBOpenDBRequest = indexedDB.open(IDBName, IDBVersion);

    IDBOpenDBRequest.onupgradeneeded = function(e) {

        var _db = e.target.result;

        createObjectStore(_db, "students");

        deleteObjectStore(_db, "firstOS");

        console.log('DB version changed to ' + IDBVersion);

    }

    IDBOpenDBRequest.onsuccess = function(e) {

        dataBase = e.target.result;

        // addData(dataBase,"students");

        // getDataByKey(dataBase,"students",1001);

        updateDataByKey(dataBase, "students", 1001);

        console.log("openIDB Success!");

    }

    IDBOpenDBRequest.onerror = function(e) {

        console.log("Error:" + e.currentTarget.error.message);

    }

}

// 添加数据

function addData(db, storeName) {

    var transaction = db.transaction(storeName, 'readwrite');

    var store = transaction.objectStore(storeName);

    for (var i = 0; i < students.length; i++) {

        store.add(students[i]);

    }

}

// 查询数据(根据关键字)

function getDataByKey(db, storeName, keyValue) {

    var transaction = db.transaction(storeName, 'readonly');

    var store = transaction.objectStore(storeName);

    var request = store.get(keyValue);

    request.onsuccess = function(e) {

        var student = e.target.result;

        console.log(student.name);

    };

}

// 更新数据

function updateDataByKey(db, storeName, keyValue) {

    var transaction = db.transaction(storeName, 'readwrite');

    var store = transaction.objectStore(storeName);

    var request = store.get(keyValue);

    request.onsuccess = function(e) {

        var student = e.target.result;

        student.age = 35;

        store.put(student);

    };

}

// 删除数据

function deleteDataByKey(db, storeName, keyValue) {

    var transaction = db.transaction(storeName, 'readwrite');

    var store = transaction.objectStore(storeName);

    store.delete(keyValue);

}

// 清空Store

function clearObjectStore(db, storeName) {

    var transaction = db.transaction(storeName, 'readwrite');

    var store = transaction.objectStore(storeName);

    store.clear();

}

// 删除Store(在onupgradeneeded里调用)

function deleteObjectStore(db, storeName) {

    if (db.objectStoreNames.contains(storeName)) {

        db.deleteObjectStore(storeName);

        console.log("deleteObjectStore:" + storeName + "，成功！");

    }

}

// 关闭dataBase

function closeIDB(db) {

    db.close();

}

// 删除dataBase

function deleteIDB(db) {

    indexedDB.deleteDatabase(db);

}

// 新增Store(在onupgradeneeded里调用)

function createObjectStore(db, storeName) {

    if (!db.objectStoreNames.contains(storeName)) {

        db.createObjectStore(storeName, {

            autoIncrement: true

        });

        console.log("createObjectStore:" + storeName + "，成功！");

    }

}

// 新增Store--带索引(在onupgradeneeded里调用)

function createObjectStoreWidthIndex(db, storeName) {

    if (!db.objectStoreNames.contains(storeName)) {

        var store = db.createObjectStore(storeName, {

            keyPath: "id"

        });

        // 创建两个索引表

        store.createIndex('nameIndex', 'name', {

            unique: true

        });

        store.createIndex('ageIndex', 'age', {

            unique: false

        });

        console.log("createObjectStore:" + storeName + "，成功！");

    }

}

// 获取数据(根据索引)

function getDataByIndex(db, storeName) {

    var transaction = db.transaction(storeName, 'readonly');

    var store = transaction.objectStore(storeName);

    var index = store.index("nameIndex");

    index.get('Byron').onsuccess = function(e) {

        var student = e.target.result;

        console.log(student.id);

    }

}

// 使用游标

function fetchStoreByCursor(db, storeName) {

    var transaction = db.transaction(storeName, 'readonly');

    var store = transaction.objectStore(storeName);

    var request = store.openCursor();

    request.onsuccess = function(e) {

        var cursor = e.target.result;

        if (cursor) {

            console.log(cursor.key);

            var currentStudent = cursor.value;

            console.log(currentStudent.name);

            cursor.continue();

        }

    };

}

// 索引与游标结合

function getDataByMultiple(db, storeName) {

    var transaction = db.transaction(storeName);

    var store = transaction.objectStore(storeName);

    var index = store.index("ageIndex");

    // index.openKeyCursor(26);

    var request = index.openCursor(IDBKeyRange.only(26));

    request.onsuccess = function(e) {

        var cursor = e.target.result;

        if (cursor) {

            var student = cursor.value;

            console.log(student.id);

            cursor.continue();

        }

    }

}

// 指定游标范围

// IDBKeyRange.only(value)：只获取指定数据

// IDBKeyRange.lowerBound(value,isOpen)：获取最小值是value的数据

// IDBKeyRange.upperBound(value,isOpen)：获取最大值是value的数据

// IDBKeyRange.bound(value1,value2,isOpen1,isOpen2)

if (hasIndexedDB()) {

    openIDB("test1", 2);

}