CREATE EVENT - MySQL

Overview

The CREATE EVENT command in MySQL is used to create and schedule the execution of an event at specific intervals. It automates tasks, simplifies maintenance, and ensures consistency by executing predefined actions at designated times.

Syntax

CREATE EVENT event_name
  ON SCHEDULE schedule
DO
  event_body

Parameters

  • event_name: A unique name for the event.
  • schedule: Defines the timing and recurrence of the event’s execution, including date, time, and intervals.
  • event_body: The SQL statement(s) or PL/SQL block to be executed when the event is triggered.

Options/Flags

  • DEFINER: Specifies the user who owns the event. (Default: current user)
  • ON COMPLETION: Determines the action to take after the event’s execution (e.g., PRESERVE, DROP).
  • ENABLE/DISABLE: Controls whether the event is active or not. (Default: ENABLE)
  • COMMENT: Adds a comment to the event for documentation purposes.

Examples

Create an event to execute a backup script at midnight every day:

CREATE EVENT daily_backup
ON SCHEDULE EVERY 1 DAY AT '00:00:00'
DO
  CALL backup_procedure();

Create an event to send a reminder email every Monday:

CREATE EVENT reminder_email
ON SCHEDULE EVERY 1 WEEK ON MONDAY AT '09:00:00'
DO
  CALL send_reminder_email();

Common Issues

  • Ensure the user has the EVENT privilege to create events.
  • Check the DEFINER permissions and ensure the user has execute privileges on the event’s body.
  • Verify the syntax of the schedule expression and ensure it follows the correct format.
  • Handle errors in the event body using exception handling mechanisms (e.g., BEGIN ... EXCEPTION ... END).

Integration

  • Use the ALTER EVENT command to modify existing events.
  • Integrate with other commands like CALL and SELECT to execute stored procedures and retrieve data within the event body.
  • Utilize the MySQL Event Scheduler API to programmatically manage events.
  • DROP EVENT: Removes an event.
  • SHOW EVENTS: Lists all events in a given database.
  • ALTER EVENT: Modifies the properties and schedule of an existing event.