The Save Method
Eloquent provides convenient methods for adding new models to relationships. For example, perhaps you need to insert a new Comment for a Post model. Instead of manually setting the post_id attribute on the Comment, you may insert the Comment directly from the relationship's save method:
$comment = new App\Comment(['message' => 'A new comment.']);
$post = App\Post::find(1);
$post->comments()->save($comment);
Notice that we did not access the comments relationship as a dynamic property. Instead, we called the comments method to obtain an instance of the relationship. The save method will automatically add the appropriate post_id value to the new Comment model.
If you need to save multiple related models, you may use the saveMany method:
$post = App\Post::find(1);
$post->comments()->saveMany([
new App\Comment(['message' => 'A new comment.']),
new App\Comment(['message' => 'Another comment.']),
]);
The save and saveMany methods will not add the new models to any in-memory relationships that are already loaded onto the parent model. If you plan on accessing the relationship after using the save or saveMany methods, you may wish to use the refresh method to reload the model and its relationships:
$post->comments()->save($comment);
$post->refresh();
// All comments, including the newly saved comment...
$post->comments;
Recursively Saving Models & Relationships
If you would like to save your model and all of its associated relationships, you may use the push method:
$post = App\Post::find(1);
$post->comments[0]->message = 'Message';
$post->comments[0]->author->name = 'Author Name';
$post->push();