On Nov 13, 2007 11:39 AM, Baron Schwartz <[EMAIL PROTECTED]> wrote: > InnoDB can also lock the gap, which will prevent new rows that would > have been returned by the SELECT. The manual has more info on this in > the section on consistent reads in InnoDB. FOR UPDATE will do what you > need.
Interesting, I didn't think that would work, but the manual does say it will: "You can use next-key locking to implement a uniqueness check in your application: If you read your data in share mode and do not see a duplicate for a row you are going to insert, then you can safely insert your row and know that the next-key lock set on the successor of your row during the read prevents anyone meanwhile inserting a duplicate for your row. Thus, the next-key locking allows you to "lock" the non-existence of something in your table." http://dev.mysql.com/doc/refman/5.0/en/innodb-next-key-locking.html There's another suggestion in the comments on that page: INSERT IGNORE and then check the number of rows affected. But, not portable to SQLite. - Perrin P.S. I enjoy your blog, Baron. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
