MySQL will soon store FOREIGN KEY definitions so that a client can ask for and receive an answer about how the original connection was made. The current `.frm' file format does not have any place for ...

Can you do a foreign key within a single table, though? I've only ever seen foreign key constraints tying a field in one table to a field in another table.

Oracle announced the general availability of MySQL Cluster 7.3, which adds foreign key support, a new NoSQL JavaScript Connector for node.js, and an auto-installer to make setting up clusters easier.

I wouldn't drop and add a foreign key just to modify data. In Oracle and MySQL you can temporarily disable foreign key checks.