Question

I have tables: user, comment and post, say:

1. A user can have many posts and comments
2. A post can have many comments
3. A comment can only be written by one user, and can only be in one post

So, how can I make the relations between those tables, in way that results in no closed relation.

this is what I did :

tbl_user 1 ------ n  Post 
tbl_post 1--------n Comments

Answer 1

I think your approach is good, but you should also establish a tbl_user: 1..n Comment relationship (assuming not only the owner of a post can make a comment) to identify the relationship between the comment and its owner.