IDBObjectStore.openKeyCursor()
The openKeyCursor() method of the
IDBObjectStore interface returns an IDBRequest object
whose result will be set to an IDBCursor that can be used to iterate
through matching results. Used for iterating through the keys of an object store with
a cursor.
To determine if the add operation has completed successfully, listen for the
results's success event.
Syntax
var request = objectStore.openKeyCursor();
var request = objectStore.openKeyCursor(query);
var request = objectStore.openKeyCursor(query, direction);
Parameters
- query Optional
-
The key range to be queried. If a single valid key is passed, this will default to a range containing only that key. If nothing is passed, this will default to a key range that selects all the records in this object store.
- direction Optional
-
An
IDBCursorDirectiontelling the cursor what direction to travel. Valid values are"next","nextunique","prev", and"prevunique". The default is"next".
Return value
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:
InvalidStateErrorDOMException-
Thrown if this
IDBObjectStoreorIDBIndexhas been deleted. TransactionInactiveErrorDOMException-
Thrown if this
IDBObjectStore's transaction is inactive. DataErrorDOMException-
Thrown if the specified key or key range is invalid.
Example
In this simple fragment we create a transaction, retrieve an object store, then use a cursor to iterate through all the records in the object store:
var transaction = db.transaction("name", "readonly");
var objectStore = transaction.objectStore("name");
var request = objectStore.openKeyCursor();
request.onsuccess = function(event) {
var cursor = event.target.result;
if(cursor) {
// cursor.key contains the key of the current record being iterated through
// note that there is no cursor.value, unlike for openCursor
// this is where you'd do something with the result
cursor.continue();
} else {
// no more results
}
};
Specifications
| Specification |
|---|
| Indexed Database API 3.0 # ref-for-dom-idbobjectstore-openkeycursor① |
Browser compatibility
BCD tables only load in the browser
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.)