Implement hasOne() relationship ID binding.

[romaninsh]

When populating model that contains hasOne() relation, sometimes you want to also populate the related entity. This should nicely place the ID of a new record into the main table:

$m = new Model_User($db);

$m['name'] = 'John';
$m->ref('address_id')->save(['address'=>'street']);
$m->save();

This should also save $m['address_id'];

[DarkSide666]

Do we need afterSave hook here even if referenced model can be loaded? This is good if we allow to change id of model, but ... do we allow that?

[romaninsh]

That is a very good point. I'm not sure which one is better.

[DarkSide666]

I don't think agile/data supports changing model id. Can we do:

$m->load(1);
$m['id'] = 2;
$m->save(); // update table set id=2 where id=1 ??? do this work or will create insert instead?

[romaninsh]

OK, i think i want to keep as-is for the following pattern:

$user->ref('contact_id')->load(123)->save();

which allows to easily update to a different record.