I am getting this message:

Mysql::Error: Duplicate entry '0-0-0-0-0-0' for key 1: INSERT INTO core_contents_resources () VALUES ()
When trying to insert informaiton into a many-to-many table. The core_contents_resources table has 6 fields (1 from core_contents, 5 from resources (4 of those are foriegn keys from other one-to-many tables)). I am inserting via:

@resource.core_contents << CoreContent.find(@params[:core_content_ids]) if @params[:core_content_ids]
I don't know the issue and can't seem to find any help.