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:
Exception | Description |
---|---|
InvalidStateError |
This IDBObjectStore or IDBIndex has been deleted. |
TransactionInactiveError |
This IDBObjectStore 's transaction is inactive. |
DataError |
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 } };
Specification
Specification | Status | Comment |
---|---|---|
Indexed Database API The definition of 'openCursor()' in that specification. |
Recommendation | |
Indexed Database API 2.0 The definition of 'openCursor()' in that specification. |
Editor's Draft |
Browser compatibility
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.)