IDBTransaction.mode

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范例
规范
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mode 只读特性在 IDBTransaction interface returns the current mode for accessing the data in the object stores in the scope of the transaction (i.e. is the mode to be read-only, or do you want to write to the object stores?) The default value is readonly .

注意： 此特征可用于 Web 工作者 .

句法

var myCurrentMode = IDBTransaction.mode;

值

IDBTransactionMode object defining the mode for isolating access to data in the current object stores:

值	解释
`readonly`	Allows data to be read but not changed.
`readwrite`	Allows reading and writing of data in existing data stores to be changed.
`versionchange`	Allows any operation to be performed, including ones that delete and create object stores and indexes. This mode is for updating the version number of transactions that were started using `IDBDatabase.setVersion()` . Transactions of this mode cannot run concurrently with other transactions. Transactions in this mode are known as "upgrade transactions."

范例

In the following code snippet, we open a read/write transaction on our database and add some data to an object store. Note also the functions attached to transaction event handlers to report on the outcome of the transaction opening in the event of success or failure. At the end, we simply log the mode of the current transaction using mode . For a full working example, see our 待办通知 app ( 实时查看范例 )。

// Let us open our database
var DBOpenRequest = window.indexedDB.open("toDoList", 4);
DBOpenRequest.onsuccess = function(event) {
  note.innerHTML += '<li>Database initialised.</li>';
  // store the result of opening the database in the db variable.
  // This is used a lot below
  db = DBOpenRequest.result;
  // Run the addData() function to add the data to the database
  addData();
};
function addData() {
  // Create a new object ready for being inserted into the IDB
  var newItem = [ { taskTitle: "Walk dog", hours: 19, minutes: 30, day: 24, month: "December", year: 2013, notified: "no" } ];
  // open a read/write db transaction, ready for adding the data
  var transaction = db.transaction(["toDoList"], "readwrite");
  // report on the success of opening the transaction
  transaction.oncomplete = function(event) {
    note.innerHTML += '<li>Transaction completed: database modification finished.</li>';
  };
  transaction.onerror = function(event) {
    note.innerHTML += '<li>Transaction not opened due to error. Duplicate items not allowed.</li>';
  };
  // create an object store on the transaction
  var objectStore = transaction.objectStore("toDoList");
  // add our newItem object to the object store
  var objectStoreRequest = objectStore.add(newItem[0]);
  objectStoreRequest.onsuccess = function(event) {
    // report the success of the request (this does not mean the item
    // has been stored successfully in the DB - for that you need transaction.onsuccess)
    note.innerHTML += '<li>Request successful.</li>';
  };
  // Return the mode this transaction has been opened in (should be "readwrite" in this case)
  transaction.mode;
};

规范

规范	状态	注释
索引数据库 API 2.0 The definition of 'mode' in that specification.	推荐
索引数据库 API 草案 The definition of 'mode' in that specification.	推荐

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`mode`	Chrome 24 24 23 Prefixed Prefixed Implemented with the vendor prefix: webkit	Edge 12	Firefox 16 16 10 — 16 Prefixed Prefixed Implemented with the vendor prefix: moz	IE 部分支持 10	Opera 15	Safari 7	WebView Android Yes	Chrome Android Yes	Firefox Android 22	Opera Android 14	Safari iOS 8	Samsung Internet Android Yes

图例

完整支持
部分支持
要求使用供应商前缀或不同名称。

另请参阅

使用 IndexedDB
开始事务： IDBDatabase
使用事务： IDBTransaction
设置一系列键： IDBKeyRange
检索并使您的数据改变： IDBObjectStore
使用光标： IDBCursor
参考范例：待办通知 ( 实时查看范例 )。

元数据

最后修改： 2020 年 1 月 22 日

IndexedDB API
IDBTransaction
特性
1. db
2. error
3. mode
4. objectStoreNames
5. onabort
6. oncomplete
7. onerror
方法
事件
1. abort
2. complete
继承：
1. EventTarget
IndexedDB 相关页面

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句法

值

范例

规范

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图例

另请参阅

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