Multiple yet mutually exclusive foreign keys - is this the way to go?

Question

I have three tables: Users, Companies and Websites. Users and companies have websites, and thus each user record has a foreign key into the Websites table. Also, each compa

Answer 1

First of all, do you really need this bi-directional link? It is a good practice to avoid it unless absolutely needed.

I understand it that you wish to know whether the site belongs to a user or to a company. You can achieve that by having a simple boolean field in the Website table - [BelongsToUser]. If true, then you look up a user, if false - you look up a company.