Bulk Update Listener¶
Listeners for bulk update work very similarly to the ones for single oject update. The differences between single object and bulk update include the method names to add and remove listener objects as well as the object delivered to the listener.
Conditional bulk update listener¶
When an API client executes a bulkUpdate
API request using the same whereClause
value as the one specified in addBulkUpdateListener
, the listener receives a real-time event.
const eventHandler = Backendless.Data.of( 'TABLE-NAME' ).rt();
const callback = ({ whereClause, count }) => console.log( whereClause, count )
const onError = ({ message, code }) => console.log( 'Error:', message, 'Error Code:', code )
eventHandler.addBulkUpdateListener( whereClause, callback, onError );
const eventHandler = Backendless.Data.of( TABLENAMECLASS ).rt();
const callback = ({ whereClause, count }) => console.log( whereClause, count )
const onError = ({ message, code }) => console.log( 'Error:', message, 'Error Code:', code )
eventHandler.addBulkUpdateListener( whereClause, callback, onError );
Unconditional bulk update listener¶
A registered listener will receive a real-time request for all bulkUpdate
API requests.
const eventHandler = Backendless.Data.of( 'TABLE-NAME' ).rt();
const callback = ({ whereClause, count }) => console.log( whereClause, count )
const onError = ({ message, code }) => console.log( 'Error:', message, 'Error Code:', code )
eventHandler.addBulkUpdateListener( callback, onError );
const eventHandler = Backendless.Data.of( TABLENAMECLASS ).rt();
const callback = ({ whereClause, count }) => console.log( whereClause, count )
const onError = ({ message, code }) => console.log( 'Error:', message, 'Error Code:', code )
eventHandler.addBulkUpdateListener( callback, onError );
For both conditional and unconditional update listeners, the object received in the callback contains the following properties:
whereClause
- the where clause value used in the API call to identify the objects updated in the database.count
- the number of objects updated in the database.
Removing listeners¶
The method removes all registered listeners for the bulk update event:
eventHandler.removeBulkUpdateListeners();
The method below removes all listeners which process events for a specific where clause.
The value of the whereClause
argument must be the same as one in the addBulkUpdateListener
method:
eventHandler.removeBulkUpdateListeners( whereClause );
Removing a specific listener¶
This method removes a listener identified by the callback object:
eventHandler.removeBulkUpdateListener( callbackObject );