Artificial primary keys in many-to-many relationships

Sergio González (IT teacher) il y a 2 ans mis à jour par Adam Mościcki il y a 2 ans 1

Checking your article "A Dating App Data Model" I saw that in relations that appear from a many-to-many relationship (for instance between relations "user_account" and "gender") you add an artificial primary key (in the case exposed, primary key is a numeric field "id" but the primary key should be the combination of "user_account_id" and "gender_id").

Is there a technical reason to do that?


Thanks for the answer!

Note de satisfaction par Sergio González (IT teacher) il y a 2 ans

Hello Sergio,

You are right, the primary key is an artifical (surrogate) primary key.

To be honest, I don't know the reason. 

The best way to get the answer is to ask directly in the article: https://www.vertabelo.com/blog/a-dating-app-data-model/

Hope this helps,