# Generated Event Handlers

> Event statements in the database schema declare events that the application will be notified of, such as: adding a new object, deleting an object, updating an object or a specified field of an object (with the exception of array and vector fields), and checkpoint events. The DDL compiler generates handlers for the events which can be registered with the runtime to be called synchronously.

> The following functions are generated for event handlers specified in the schema:

> mco_register_eventname_handler() | Register a call-back function for an add, delete or checkpoint event
> mco_register_eventname_handler(update) | Register a call-back function for an update event
> mco_unregister_eventname_handler() | Unregister a call-back function