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);
}