Question

This is more or less a best-practice question:

I’m working on a site that requires me to relate some tables to several different tables.
For instance, I have a Comments-table, that I would like to relate in a way such as one might comment on entities in Table A, but also in Table B separately.

Similarly, I have a rating-table that I would like to do the same with, so that one could rate different aspects in the site.

I’ve touched upon one method that implies having a loose relation with a Relationships-table with a PrimaryKey(Guid) and ForeignKey(Guid), and then using Guids as Primary key in both the Comments-table and the Rating-table – However this implies I’m gonna need Guid as primary key in the other tables as well.

Anyone have any great ideas here? Greatly appreciated 🙂

PS. If it’s interesting, I’m creating an ASP.NET MVC2 app with an ORM (either EF, Linq2Sql or NHibernate.. doesn’t really matter :))

Answer 1

You could use a single comments/ratings table, but use a separate table for each related entity to maintian the comment to entity relationship. If you had Posts and Pages, each with comments, it would look something like this:

Comments
 - CommentID
 - CommentText

Posts
 - PostID
 - Other fields

Pages
 - PageID
 - Other fields

PostComments
 - PostID
 - CommentID

PageComments
 - PageID
 - CommentID