At the moment I'm not quite sure how the relations with the databases work. (bumping)

For my system I need three parts to it.

First part - normal user, normal privileges:
The normal user submits a form telling more about themselves. Each normal user can only have one table row. If they submit it twice it updates the previous submission.

Second part - stage two user, a bit more privileges:
The stage two users give their opinion about a single user, and they can submit only one submission per user. If they submit twice on the same user it just updates the row submitted before.

Third part - stage three user, same privileges as stage two:
The stage three users are another group to give submissions about a user. Same as stage two, they can only submit one for each user, updating if they submit twice.