Mysql_Trigger.md

DELIMITER $$
CREATE TRIGGER Prevent_User_From_Insert_Empty_Strings BEFORE INSERT ON users
FOR EACH ROW
BEGIN
   IF NEW.name = '' THEN
       SIGNAL SQLSTATE '45000';
   END IF;
END;

This example shows how to use MySQL trigger to prevent the user from adding an empty string to the name field in the users table.

This could be handy in case if we want to add another validation layer to our application ( keep in mind that this might decrease the performance a bit ).