DataMapper ORM v1.8.2

[eluser]WanWizard[/eluser]
Datamapper doesn't support three-way relationships, so you can't do this.

You can work around that my making a model for the relationship table, and convert the many-to-many between users and friends to one-to-many's with this new model. You can then make a one-to-many between the new model and relationships.

You can then run your queries from the perspective of this new model. To make it easier you could add some helper methods to this new model, for example:

Code:

public function all_friends_of_user($userid)
{
    // get the friends of this user as friend model objects
    $this->where('user_id', $userid)->include_related('friend', NULL, TRUE, TRUE)->get();

    // $this->friend now contains all related friends
    return $this;
}