转储中的 MySQL 标志 [英] MySQL flags in dumps
问题描述
在查看 mySQL Dump 时,我遇到了一些事情并且想知道它们是什么.
我明白了:
/*!50001 DROP TABLE IF EXISTS `xxx` */;
标志 50001 是什么,有没有列出它们的含义?
它在 MySQL 的论坛/邮件列表中讨论 此处.
<块引用>/*!50001 DROP TABLE `category_count_view`*/;
这是 MySQL 的一个特性".任何其他 RDBMS 都会将此视为评论.
但是,MySQL 查看 50001 并将其检查为 MySQL 版本.这是版本 5.00.01,或现实世界中的 5.0.1,但为子版本和版本大于9.
如果 MySQL 低于 5.0.1,MySQL 会将该行视为注释,并且如果 MySQL 大于或等于 5.0.1,将处理该行.
这是一种使 SQL 脚本兼容不同版本的方法MySQL,并允许包含新功能.
Looking at a mySQL Dump, I have come across something and like to know what they are.
I see:
/*!50001 DROP TABLE IF EXISTS `xxx` */;
What is the flag 50001, is there a list of what they mean?
It is discussed on the MySQL's forums/mailing lists here.
/*!50001 DROP TABLE `category_count_view`*/;
This is a "feature" of MySQL. Any other RDBMS will treat this as a comment.
But, MySQL looks at 50001 and checks that as a MySQL version. This is Version 5.00.01, or 5.0.1 in the real world, but leaves room for the the sub-version and release to be greater than 9.
MySQL will treat the line as a comment if MySQL is below 5.0.1, and will process the line if MySQL is greater than or equal to 5.0.1.
It's a way making a SQL script compatible with different versions of MySQL, and allows new features to be included.
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