Can DB::transaction() execute Eloquent queries as transaction?

0
votes

Me: THIS IS A HYBRID QUESTION | Visitor: (wtf?) what this means?

I'm asking 2 questions in one (as it tightly coupled)

Using: Laravel 5.5 & Mysql

1. How do I delete related models in eloquent?

I'm trying to delete User which has the following relations

belongsTo Address, belongsTo Package, hasMany Orders, hasMany Comments

Orders cascade when User or Product gets deleted COmments cascade when User or Post gets deleted.

Now how do I can delete User & automatically have associated orders & comments deleted?

when I try to delete with $user->delete() laravel throws exception:

SQLSTATE[23000]: Integrity constraint violation: 1451 Cannot delete or update a parent row: a foreign key constraint fails (`cybertron`.`comments`, CONSTRAINT `comments_user_id_foreign` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`)) (SQL: delete from `users` where `id` = 4)

So I decided to use a transaction to delete, User, associated orders & comments, To make sure everything gets deleted.

But I didn't find any transaction in eloquent but in query builder (DB).

2. if I use transaction from DB & use eloquent to delete user ($user->delete) will this consider as a transaction?

like:

DB::transaction(function() {

      $user->comments->delete();
      $user->orders->delete();
      $user->delete();
});

If not then how can I have a transaction with Eloquent ?

Any help will be greatly appreciated

2
phplaraveltransactionseloquentlaravel-5.5

2 Answers

2
votes

  1. You have Eloquent events For deleting but you can also override default delete method like so:

    public function delete()
{
    \DB::transaction(function() {
        $this->comments()->delete();
        $this->orders()->delete();
        parent::delete(); 
     });
}

  2. Yes, Eloquent doesn't have transaction itself. You use transactions as you showed and wrap Eloquent or query builder in it. Be aware that in your case you should use comments() and orders() instead of comments and orders

1
votes

@Marcin

if you are using events on model, in order to cascade delete, you need to make sure you understand differences between running delete on a Query object vs running delete on a Model object

For example : $this->orders()->delete(); - this line is not actually loading Order models - $this->orders() - returns a Query Object - this line will actually run a DELETE SQL statement

In order to launch deleting event on order when deleting a user, you would have to do a foreach foreach($user->orders as $order) $order->delete();

when user::deleting event is launched, load all orders of the user and call delete; this will fire order::deleting event where we are going to load all comment Objects and delete them also