The SIGNAL statement rolls back the changes that were attempted by the triggering statement (that is, our update statement).
SIGNAL 语句回滚由触发语句(也就是我们的 update 语句)尝试的更改。
The statement that causes a triggering event might affect multiple rows in the database.
引起触发事件的语句可能会同时影响数据库中的多行。
You specify that only files are selected in the find statement to prevent changes to directories triggering the inclusion of files that have not changed into the tar file.
您可以在find语句中仅指定需要选择的文件,这样可以防止对目录的更改导致将那些没有更改的文件包含到tar文件中。
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