creating a foreign key like relationship with custom post types

Question

I am currently building a website, that is heavily reliant on custom post types, 2 of my custom post types are "Clients" and "Case Studies", now what I am wanting is a way to create a dropdown in the "Case Studies" custom post type so that I can select from the Clients that have already been added to the site? Is this possible, I assume it would be similar creating a relationship in database, and then pulling in the clients from the clients and table and placing them in a <select>.

Answer 1

You can create relationships between posts / pages with the Posts 2 Posts plugin. (more info on the wiki)

You could then create a connexion between Case Studies and Clients, and associate them accordingly.

For clarity, you should ask your second question in a separate question, as it is not related to the title of this thread.