IDBObjectStore.openCursor()
The openCursor()
method of the
IDBObjectStore
interface returns an IDBRequest
object,
and, in a separate thread, returns a new IDBCursorWithValue
object.
Used for iterating through an object store with a cursor.
To determine if the add operation has completed successfully, listen for the results's
success
event.
Note: This feature is available in Web Workers
Syntax
var request = ObjectStore.openCursor();
var request = ObjectStore.openCursor(query);
var request = ObjectStore.openCursor(query, direction);
Parameters
- query Optional
-
A key or
IDBKeyRange
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.openCursor();
request.onsuccess = function(event) {
var cursor = event.target.result;
if(cursor) {
// cursor.value contains the current record being iterated through
// 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-opencursor② |
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.)