Question

When designing a relationship in Datamapper one is bound to call the relationship the same name as the related object, which is not too handy when you have something like Application_Model_User as a class name. For those of you who will rush to say that there is a configuration option with “class” key, I know. Been there tried that. It only works for getting a related object, not for updating them.

Here is a code snippet to reproduce the problem:

// User Model
class UserModel extends Datamapper
{
    public $table = 'users';
    public $has_many = array(
        'roles' => array(
            'class' => 'RoleModel',
            'other_field' => 'usermodel',
            'join_other_as' => 'role',
            'join_self_as' => 'user',
            'join_table' => 'users_roles' 
        ),
    );
}

class RoleModel extends DataMapper
{
    public $table = 'roles';
    public $has_many = array(
        'usermodel' => array('class'        => 'UserModel',
                         'other_field'  => 'roles',
                         'join_other_as'=> 'user',
                         'join_self_as' => 'role',
                         'join_table'   => 'users_roles' )
    );
}

// controller code. Make sure you have a role with INT id = 2, and a user with INT id = 5 in your db
$user = new UserModel(2);
$role = new RoleModel(5);
$user->save($role);

This code gives an “Unable to relate usermodel with rolemodel.” error, however it does work properly (meaning a new record is inserted in the join table user_roles) if the relation is renamed from “roles” to “rolemodel”.

So, if there are any avid users of CI’s Datamapper that could help, please let me know how to properly define relationships.

Answer 1

UPDATE

You can save an object as a relation using the relationship key:

$object->save( $related, $relationship_key ). 

So you would need to use

$user->save($role, "roles");

See the bottom of this web page:
http://datamapper.wanwizard.eu/pages/save.html

---

Leaving this bit in case it helps someone else out.

It looks like you want to have a custom name on a relationship. (That’s what I get after wading through all of the cynicism) –

You get to name the relationship anything that you want with the key in the relationship array. So, in the following snippet, you use book <– this does or does not have to be the same name as the class – that’s what the class key is for.

class Author extends DataMapper {
  $has_many = array(
    'book' => array(  // YOU USE THIS KEY TO NAME THE RELATIONSHIP
        'class' => 'book',
        'other_field' => 'author',
        'join_self_as' => 'author',
        'join_other_as' => 'book',
        'join_table' => 'authors_books'
     )
  );
}

If this is not working for you, my guess is you have something else wrong in the set up of your relationships.

http://datamapper.wanwizard.eu/pages/advancedrelations.html