Laravel 4 - Eager loading

eloquent_eager_loading

Assume we have a following situation:
    - We have a task that has associated checklists (one or many). 
    - Every checklist has associated items (again, one or many).

In Laravel 4, we can use Eager Loading to fetch all associated data.

Let's take a look.

First, we have have a TaskChecklistItem model as following:

    // nothing special, regular Eloquent model
    class TaskChecklistItem extends Eloquent{
    
        protected $table = 'taskchecklistitems';
    
        /**
        * Mass fillable fields
        *
        * @var array
        */
        protected $fillable = array('description', 'task_checklist_id', 'is_done', 'order');
    }
    
Next, we'll have TaskChecklist model, that has defined relationship to checklist items. Something like this:

    class TaskChecklist extends Eloquent{
    
        protected $table = 'taskchecklists';
    
        /**
        * Mass fillable fields
        *
        * @var array
        */
        protected $fillable = array('title', 'task_id');
        
        public function items(){
            return $this->hasMany('TaskChecklistItem');
        }
    }
    
In the end, we have Task model defined like this:

    class Task extends Eloquent {
        /**
        * Mass fillable fields
        *
        * @var array
        */
    
        protected $fillable = array('title', 'description', 'order', 'points_id', 'user_id', 'board_id',
                                    'status_id', 'priority_id', 'type_id', 'sprint_id', 'done_at', 
                                    'doer_id', 'parent_id');
    
        
        public function checklists(){
            return $this->hasMany('TaskChecklist');
        }
    }
    
Now, when we're fetching data for task, and want to fetch all related checklists and their items, we can do it like this:

Task::with(array('checklists', 'checklists.items'))->where('tasks.id', $taskId)->get();

and it will fetch all data that we need. As simple as that.