Many to many and eager loading laravel

Question

I have a task manager and each user can be assigned task. I have these 4 databases (I'm only showing the columns needed for this discussion)

users:

--------------------------
|   id   |   username      |  
---------------------------
|   1    |    peterg      |    
 ----------------------------
|   2    |     louisg        |      
----------------------------

tasks:

-----------------------------------------------------
|   id   |     title        |     project_id         |
------------------------------------------------------
|   1    |   Finsih hw       |          1           |
 ---------------------------------------------------
|   2    |      cut grass       |       4         |
----------------------------------------------------

a pivot table for users and tasks user_task:

----------------------------------------------
|   id   |   task_id     |     user_id      |
---------------------------------------------
|   1    |       1       |      1          |
 --------------------------------------------
|   2    |      1        |      2         |
---------------------------------------------
|   1    |       2       |      2         |
 --------------------------------------------
|   1    |       2       |      4          |
 --------------------------------------------

and finally my projects table:

---------------------------
|   id   |      title         |
-----------------------------
|   1    |    first_title     |
 ---------------------------
|   2    |     second_title     |   
------------------------------

here is the user relationship with tasks

public function assignedTasks()
{
    return $this->belongsToMany('RL\Tasks\Task', 'user_task')
        ->orderBy('priority', 'ASC')
        ->orderBY('created_at', 'DESC')
        ->where('stage', '=', 1);
}

My Laravel route to show this page is /{username}/assigned-task so when this route is hit a have a service class that fetches all the task for that user

public function assignedTasks($username)
{
    $user = $this->member->getUserIdByUsername($username);

    if(!$user) throw new UsernameNotFoundException;

    $tasks = $user->assignedTasks;

    return $tasks;
}

my html to dislay the assigned tasks:

<div id="assignments">
@foreach(array_chunk($tasks->all(), 3) as $row)
        <div class="row">
        <?php $task_id = [];?>
            @foreach($row as $task)
                <div class="col-md-4">
                    <div class="panel panel-default">
                      <div class="panel-heading">
                        <h3 class="panel-title">{{$task->title}}.</h3>
                      </div>
                      <div class="panel-body">
                        <p>{{$task->description}}</p>
                        <p><strong>Project: </strong>{{$task->project->title}}</p>
                        <p class=""><strong>Priority: </strong>{{$task->priority}}</p>
                        <p class="right"><strong>Stage: </strong>{{$task->stage}}</p>
                        <a href="">Details</a>
                      </div>
                    </div>
                </div>
            @endforeach
        </div>
    @endforeach
</div>

This works fine but when I check the SQL I noticed that for each time i try to {{$task->project->title}} a select * from project is run so if i have 50 assigned tasks thats 50 times that sql runs. How can i eager load projects in a many to many relationship?

Answer 1

You have to use eager loading in your getUserIdByUsername($username); method.

For example it will looks like

User::with('tasks')->where('username',$username)->get(); 

Now when you wil call $tasks = $user->assignedTasks; it will fetch data only once.

Read Docs Eager Loading