How to properly save relationships in Yii2?

Question

MySQL

there is a usual dependency between the comment, post, user tables,
this is how a new comment is added, on the backend

protected function newComment($post) {
        $model = new Comment();
        if ( $model->load( Yii::$app->request->post() ) ) {
            $model->user_id = \Yii::$app->user->identity->id;
            $model->post_id = $post->id;
            $model->date = date('Y-m-d H:i:s');
            $model->save();
        }
        return $model;
    }

I feel that it is possible to make it more beautiful, since the connections are registered. something like

$comment->setPost($post);
$comment->setUser($user);

how can you bypass all these direct field calls ($model->user_id, $model->post_id) ?

Answer 1

There are no direct methods, so you can implement them yourself this way

class Comment extends CActiveRecord
{
    public function setUser(\User $user = null)
    {
        if (is_null($user))
        {
            $this->user_id = null;
        } else
        {
            $this->user_id = $user->id;
        }
    }
}

$comment = new Comment;
$comment->user = $user;
// или
$comment->setUser($user);

In fact, the scheme is much more complicated than just writing a setter for the user property.
What to do if you change the user_id property through which the user is calculated - it seems like it needs to be loaded from the database again?
Will the $user entities be identical for two different comments with the same user_id?
What if $user hasn't been saved yet? Don't allow $comment->setUser($user) to be assigned or do automatic saving in a chain (first $user, then $comment) ?
Many many many questions.
In Yii2, such complexities are not implemented, since a universal all-encompassing solution like in Doctrina or PropelORM is very slow and eats up memory. There just sometimes it is necessary to prohibit fancy logic.