MySql - Unique key based on many-to-many pivot table values

Question

I have to manage artists and albums tables.

| artists      |  | albums       |  | album_artist |
+--------------+  +--------------+  +--------------+
| id           |  | id           |  | id           |
| artist       |  | album        |  | album_id     |
| created_at   |  | created_at   |  | artist_id    |
| updated_at   |  | updated_at   |  +--------------+
+--------------+  +--------------+

Keeping in mind that this is a many-to-many relation, I do need to find a way to get the album-artist(s) pair unique, since albums may have the same name yet belonging to different artists (fe "Greatest Hits" album of 2Pac and "Greatest Hits" of Notorious BIG). Is there a known way/pattern to address this problem?

Thank you.

Answer 1

I have done it before, with creating a unique constraint on the album_id,artist_id.

This will make it possible to have albums for different artists. As the artists id will differentiate. In your migration put.

$table->unique(['album_id', 'artist_id']);

In traditional database design, this is called a composite key , which is two or more columns, which makes the table unique, in most pivot table this will be the two foreign keys .