IDBTransaction

方法

从EventTarget继承

IDBTransaction.abort

放弃本次连接的transaction的所有修改，如果当前的transaction处于回滚完毕或完成状态，则会抛出一个错误事件。

IDBTransaction.objectStore

Returns an IDBObjectStore object representing an object store that is part of the scope of this transaction.

属性

IDBTransaction.db 只读

The database connection with which this transaction is associated.

IDBTransaction.mode 只读

The mode for isolating access to data in the object stores that are in the scope of the transaction. For possible values, see the Constants section below. The default value is readonly.

IDBTransaction.error 只读

The error returned in the event of an unsuccessful transaction. Null if the transaction is not finished, is finished and successfully committed, or was aborted with IDBTransaction.abort function. Returns the same DOMError as the request object which caused the transaction to be aborted due to a failed request, or a DOMError for the transaction failure not due to a failed request (such as QuotaExceededError or UnknownError).

Event handlers

IDBTransaction.onabort 只读

The event handler for the abort event, fired when the transaction is aborted.

IDBTransaction.oncomplete 只读

The event handler for the complete event, thrown when the transaction completes successfully.

IDBTransaction.onerror 只读

The event handler for the error event, thrown when the transaction fails to complete.

模式常量

Transactions 可使用以下三种模式中的一种:

即使目前这些常量已经被废弃，但如果你需要使用它，则需要提供向下兼容方案(in Chrome the change was made in version 21)。你应当防止出现对象不存在的情况：

var myIDBTransaction = window.IDBTransaction || window.webkitIDBTransaction || { READ_WRITE: "readwrite" };

Example

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. For a full working example, see our To-do Notifications app (view example live.)

// 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 our new item going into the database
    note.innerHTML += '<li>New item added to database.</li>';
  };
};

Specifications

Browser compatibility

Known browser issues

Older versions of Google Chrome serialise all transactions. So even if you have only read-only transactions and no read-write transaction, your transactions are executed one at a time. Any subsequent transactions are not executed until read-only transactions are completed. For the status, see bug 64076.

See also

• Using IndexedDB
• Starting transactions: IDBDatabase
• Using transactions: IDBTransaction
• Setting a range of keys: IDBKeyRange
• Retrieving and making changes to your data: IDBObjectStore
• Using cursors: IDBCursor
• Reference example: To-do Notifications (view example live.)