이벤트를 생성할 때 ON COMPLETION PRESERVE 절을 사용하는 것은 무엇입니까?

mysql> Create table event_messages(ID INT NOT NULL PRIMARY KEY AUTO_INCREMENT, MESSAGE VARCHAR(255) NOT NULL, Generated_at DATETIME NOT NULL); Query OK, 0 rows affected (0.61 sec)

mysql> CREATE EVENT testing_event_without_Preserves ON SCHEDULE AT CURRENT_TIMESTAMP DO INSERT INTO event_messages(message,generated_at) Values('Without Preserve',NOW()); Query OK, 0 rows affected (0.00 sec) mysql> Select * from event_messages; +----+------------------+---------------------+ | ID | MESSAGE | Generated_at | +----+------------------+---------------------+ | 1 | Without Preserve | 2017-11-22 20:32:13 | +----+------------------+---------------------+ 1 row in set (0.00 sec) mysql> SHOW EVENTS FROM query\G *************************** 1. row *************************** Db: query Name: testing_event5 Definer: root@localhost Time zone: SYSTEM Type: ONE TIME Execute at: 2017-11-22 17:09:11 Interval value: NULL Interval field: NULL Starts: NULL Ends: NULL Status: DISABLED Originator: 0 character_set_client: cp850 collation_connection: cp850_general_ci Database Collation: latin1_swedish_ci 1 row in set (0.00 sec)