Help with Foreign Keys

[eluser]gon[/eluser]
You should use foreign keys. Not everybody does, but it makes databases more secure and consistent.

What you would get in the post / comments example is:

* you can't add a comment having the id of a non-existant post.
* you can delete a post and have all of it's comments deleted automatically, or prevent a post from being deleted if a comment exists (depending on how you create the key).

You would link the same way posts and users, assuring that every post has a real user assigned, etc.