The clear()
method of the IDBObjectStore
interface creates and immediately returns an IDBRequest
object, and clears this object store in a separate thread. This is for deleting all the current data out of an object store.
Clearing an object store consists of removing all records from the object store and removing all records in indexes that reference the object store.
SyntaxEdit
var request = objectStore.clear();
Returns
An IDBRequest
object on which subsequent events related to this operation are fired.
Exceptions
This method may raise a DOMException
of one of the following types:
Exception | Description |
---|---|
ReadOnlyError |
The transaction associated with this operation is in read-only mode. |
TransactionInactiveError |
This IDBObjectStore 's transaction is inactive. |
ExampleEdit
In the following code snippet, we open a read/write transaction on our database and clear all the current data out of the object store using clear()
. 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 clearData() function to clear all the data form the object store
clearData();
};
function clearData() {
// open a read/write db transaction, ready for clearing 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: ' + transaction.error + '</li>';
};
// create an object store on the transaction
var objectStore = transaction.objectStore("toDoList");
// clear all the data out of the object store
var objectStoreRequest = objectStore.clear();
objectStoreRequest.onsuccess = function(event) {
// report the success of our clear operation
note.innerHTML += '<li>Data cleared.</li>';
};
};
SpecificationEdit
Specification | Status | Comment |
---|---|---|
Indexed Database API The definition of 'clear()' in that specification. |
Editor's Draft |
Browser compatibilityEdit
See alsoEdit
- 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.)