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
IDBCursorDirection
telling 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:
InvalidStateError
DOMException
-
Thrown if this
IDBObjectStore
orIDBIndex
has been deleted. TransactionInactiveError
DOMException
-
Thrown if this
IDBObjectStore
's transaction is inactive. DataError
DOMException
-
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.)