Eager-loading relationships in Laravel accessors?

I'd like to go back through my app and refactor bits that are noticeably slow and/or causing performance bottlenecks. The starting point for me is to address potential lazy-loading and N+1 issues.

I have the following sort of things through my app in accessors.

public function getCourseTypeLabelAttribute()
{
    return $this->courseType ? strtolower($this->courseType->name) : 'Unassigned';
}

Obviously here I'm calling course type name attribute without loading the course type in; how do I address these sorts of issues?

Sinnbeck

4 years ago

Best Answer

Level 102

Any place where you use it, be sure you eager load the relation using with('courseType')

Doing it in the accessor is too late, if you load multiple items

If you only load one item, you can in theory use lazy loading

if (! $this->relationLoaded('courseType')) {
    $this->load('courseType');
}
return $this->courseType ? strtolower($this->courseType->name) : 'Unassigned';

uniformnightly1

4 years ago

Level 1

@Sinnbeck Thanks so this would be throughout all of my controllers and other classes then, makes sense.

Sinnbeck

4 years ago

Level 102

@uniformnightly1 yeah that is best practice. I gave an example of lazy loading, but I would never recommend doing so in an accessor like this

MichalOravec

4 years ago

Level 75

@uniformnightly1 You can use a default model in your case

public function courseType()
{
    return $this->belongsTo(CourseType::class)->withDefault([
        'name' => 'Unassigned'
    ]);
}

{{ $model->courseType->name }}

Docs: https://laravel.com/docs/8.x/eloquent-relationships#default-models

2 likes

TarikAli

2 years ago

Level 2

Can we do this :

$this->loadMissing('courseType')
return $this->courseType ? strtolower($this->courseType->name) : 'Unassigned';

Snapey

2 years ago

Level 122

@TarikAli no. If you wanted to change the letter case of a field in courseType then the accessor should be in that model

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