Deleting related models one-to-many in Laravel

Question

Is this even possible? In every tutorial that I read there is nothing about deleting, only selecting and inserting related models.

This is my problem:

I have three levels of nesting. I have classes Package, Level, Lesson and Phase, and their models are below. First one - packages:

class Package extends Eloquent  {

protected $table = 'packages';
public $timestamps = false;

public function levels(){
    return $this->hasMany('Level', 'package_id');
}

}

Levels:

class Level extends Eloquent  {

protected $table = 'levels';

public function lessons(){
    return $this->hasMany('Lesson', 'level_id');
}

public function package(){
    return $this->belongsTo('Package', 'package_id');
}

}

Lessons:

class Lesson extends Eloquent {

protected $table = 'lessons';

public function phases(){
    return $this->hasMany('Phase', 'lesson_id');
}

public function level(){
    return $this->belongsTo('Level', 'level_id');
}

}

What I'm trying to do here is to when deleting one package i delete all levels related to it and also to delete all lessons related to those levels.

I have tried couple of options and they were all wrong, I just don't know how to do this without making a bunch of queries in foreach loop. Please, give some advice I'm so desperate I'm thinking about tweet to Jeffrey Way and ask him for the solution :) Thanks in advance

Answer 1

You can approach this in two ways:

1. Leverage the database to do the deleting for you. You'd add something like this to your migrations for the lessons, levels and packages, respectively:

    $table->foreign('level_id')->references('id')->on('levels')->onDelete('cascade');
   
    $table->foreign('lesson_id')->references('id')->on('lessons')->onDelete('cascade');
   
    $table->foreign('package_id')->references('id')->on('packages')->onDelete('cascade');
   

2. You can overwrite the delete method on each model to delete all of its relationships:

   class Lesson extends Eloquent {
   
       protected $table = 'lessons';
   
       public function phases(){
           return $this->hasMany('Phase', 'lesson_id');
       }
   
       public function level(){
           return $this->belongsTo('Level', 'level_id');
       }
   
       public function delete()    
       {
           DB::transaction(function() 
           {
               $this->level()->delete();
               $this->phases()->delete();
               parent::delete();
           });
       }
   
   }