How to structure database for unread item alerts per user

Question

I just have a general database theory question. I have a need to make something similar to showing what posts/items a user has viewed or not (such as in a forum) or an unread em

Answer 1

Based on this description I would use a simple table with maybe 3 columns.

1. User ID
2. Post ID
3. Timestamp First Viewed

When a user views a post, add a row to the table. If a row does not exist in the table for a given user/post id combo, then they have not viewed the post.