Should junction tables have more than one primary keys from another identifying table?

Question

Here\'s an example: Originally I have 3 tables. Table B references Table A. So now Table B has two primary keys. One used as the original primary key and the other one to en

Answer 1

You can not have more than one primary key. What you have there might be indexes. If the user_id column from table posts is included in your primary key, you can take it out and leave the primary key composed of just the id column.

I hope this helps