The mode
read-only property of the 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
.
Note: This feature is available in Web Workers.
Syntax
var myCurrentMode = IDBTransaction.mode;
Value
An IDBTransactionMode
object defining the mode for isolating access to data in the current object stores:
Value | Explanation |
---|---|
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."
|
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. At the end, we simply log the mode of the current transaction using mode
. For a full working example, see our To-do Notifications app ([[../../../../../../../mdn.github.io/to-do-notifications/index|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 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;
};
Specification
Specification | Status | Comment |
Indexed Database API 2.0The definition of 'mode' in that specification. | Recommendation | |
Indexed Database API DraftThe definition of 'mode' in that specification. | Recommendation |
Browser compatibility
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.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
mode
|
Chrome Full support 24 Full support 24 Full support 23 Prefixed' Implemented with the vendor prefix: webkit |
Edge
Full support 12 |
Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Implemented with the vendor prefix: moz |
IE
Partial support 10 |
Opera
Full support 15 |
Safari
Full support 7 |
WebView Android
Full support Yes |
Chrome Android
Full support Yes |
Firefox Android
Full support 22 |
Opera Android
Full support 14 |
Safari iOS
Full support 8 |
Samsung Internet Android
Full support Yes |
Legend
- Full support
- Full support
- Partial support
- Partial support
- Requires a vendor prefix or different name for use.'
- Requires a vendor prefix or different name for use.
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 ([[../../../../../../../mdn.github.io/to-do-notifications/index|view example live]].)
IDBTransaction.mode by Mozilla Contributors is licensed under CC-BY-SA 2.5.