Question

Lets suppose we have a football player, this player can have one or two teams ONLY, I mean he may be in a club team and/or a national team or nothing of them. what is the best way to do this in rails relation?

Answer 1

I would create has_one relationships for each team type. Perhaps you call one club_team and the other national_team. Don’t make these relationships required. This would accomplish your goal of allowing 0, 1, or 2 relationships between players and teams.

You can accomplish this by renaming the relationship in your model. For instance, if you had a model named FootballTeam then you could have two relationships like this:

has_one club_team, :class_name => "FootballTeam"
has_one national_team, :class_name => "FootballTeam"

This would also provide you with methods like player.club_team and player.national_team if player were an instance of your player model.