Laravel - calling model's method throws undefined method Illuminate\Database\Query\Builder - php

Question

I've got a problem with model's method with parameters. I've got 2 Page and ContentTranslation. I want to get ContentTranslation based on language, so I've got following method in Page model:
public function contentTranslations($language) {
return $this->hasMany('App\ContentTranslation')->where('language', $language);
}
and then I've got a method in PageController for getting the pages based on language:
public function getPagesByLanguage($language)
{
$pages = Page::orderBy('position', 'asc')->get();
foreach ($pages as $page) {
$page->contentTranslations($language);
}
$return $pages;
}
I'm returning my results in JSON format (I'm using Laravel as an api). But this approach doesn't work. It throws me error:
Call to undefined method Illuminate\Database\Query\Builder::contentTranslations()
Some time ago, I wanted to return contentTranslations for all languages, so I haven't got a parameter in contentTranslations model method and everything worked fine after calling $page->contentTranslations; in foreach loop. Why I've got the trouble with passing parameter into method?

Answer 1

You should use eager loading to avoid N+1 query problem:
public function getPagesByLanguage($language)
{
return Page::with(['contentTranslations' => function($q) use ($language) {
$q->where('language', $language);
}])
->orderBy('position', 'asc')
->get();
}
Also change your relation to:
public function contentTranslations() {
return $this->hasMany('App\ContentTranslation');
}