ON UPDATE CASCADE

[sircatsquid]

I know that you aren't suppose to have duplicate data in the database but I need to have this data as backup in these tables in case the foreign data gets removed.Like all the users in one table and lets say blog posts in an other if the user gets removed I still want the username stored in the blog table. While writing this I just realized that I might not ever remove any data just flag it out and update the sensitive columns to blank. But still going to ask is there a way to link column data to be updated between two tables like the foreign key updates if the foreign data change id. My educated guess is that this is something solved on the server side and not in SQL.

[jaseervp@ymail.com]

you can use trigger

[birbal]

check this http://dev.mysql.com/doc/refman/5.6/en/innodb-foreign-key-constraints.html