Cross-Reference Tables in WP Database

Hi, I’m attempting to create a join (cross-reference) table between the pages/posts table and the user table.

To put my goal in concrete terms: Pages and posts in my blog can correspond to a band or album review, respectfully. The feature that I am implementing will allow users to specify if they like a band/album that I write about, and then another link on the site will fire off a query to list all of the bands that they have liked.

My first attempt didn’t seem to work, although I am approaching this rather timidly because I don’t want to break anything. Has anyone seen a guide for making changes to WordPress database in this manner, or perhaps a similar manner? I’m open to other ideas if there is an easier way 🙂

Thanks!