I'm making a rails 3.2.9 app that allows users to create pages and they can embed youtube videos through a nested form.

I'm trying to figure out how to make it so that I can prevent duplicate video records from being stored in my db.

So I have a Video model that takes the youtube url and just parses out the video id and stores that instead of the full user submitted youtube url, which may have extraneous url query parameters.

So here's the situation that I'm trying to figure out:

There's page1 with video1 - url: 123 and video2 - url: abc

Then another user creates page2 and submits video3 - url: def and video4 - url: 123

Currently each page has_many videos. But I think I should change it to a many-to-many relationship. But how would I make it so that the url submitted as video4 in the nested form points to video1?

Also I how would I make a nested form that creates objects that are connected through a join table?