Insert new data with `manytomany` relationship

Let's pretend you have the following models in your application:

class Artists extends Phalcon\Mvc\Model
{
    public function initialize()
    {
        $this->hasManyToMany(
            'id',
            'ArtistsSongs',
            'artists_id',
            'songs_id',
            'Songs',
            'id'
        );
    }
}

class ArtistsSongs extends Phalcon\Mvc\Model
{

}

class Songs extends Phalcon\Mvc\Model
{

}

Then you can insert data on the many-to-many relation:

$songs = array()

$song = new Song();
$song->name = 'Get Lucky';
$songs[] = $song;

$song = new Song();
$song->name = 'Instant Crush';
$songs[] = $song;

$artist = new Artists();
$artist->name = 'Daft Punk';
$artist->songs = $songs; //Assign the n-m relation
$artist->save()

Hi, I have a similar question.

I have 2 tables: Users and Friends.

/**
 * Main Users Model
 */

namespace Models\Users;

class Main extends \Models\Main
{
    public function initialize()
    {
        $this->hasManyToMany(
            'id',
            'Models\Users\Friends',
            'user_id',
            'friend_id',
            'Models\Users\Main',
            'id', array('alias' => 'friends')
        );    
    }
}

And

/**
 * User's friends Model
 */

namespace Models\Users;

class Friends extends \Models\Main
{
}

Users is the main table that contains all users and their data. Friends is just a relations table with 2 columns: user_id and friend_id, both uses main Users table. As you see in Users I'm using hasManyToMany relationship. It works perfect while reading:

$user = \Models\Users\Main::findFirst(1);

foreach($user->friends as $friend)
{
    echo $friend->name;
}

But I can't understand how to add new friends for users. I'm trying to update:

$new_friends = array();

$user = \Models\Users\Main::findFirst(1);

$new_friends[] = \Models\Users\Main::findFirst(2);
$new_friends[] = \Models\Users\Main::findFirst(3);

$user->friends = $new_friends;

$user->save();

And this code is just adding/overwriting (expectedly) a single row:

+---------+-----------+
| user_id | friend_id |
+---------+-----------+
|       1 |         3 |
+---------+-----------+

On saving it's trying to add already existing user:

$new_friends = array();

$user = new \Models\Users\Main();

$user->name = 'New user';

$new_friends[] = \Models\Users\Main::findFirst(2);
$new_friends[] = \Models\Users\Main::findFirst(3);

$user->friends = $new_friends;

$user->save();

/**
* Integrity constraint violation: 1062 Duplicate entry 'User with id 2' for key
*/

Is it possible to solve this task without third table and additional ids? I've barely used Kohana ORM before, so the solution may be obviously for the community.

Thanks in advance!

Recently I update phalcon version to 2.0.0, but many-to-many relation between models can not work well.When I fetch records through this, it returns NULL.