Laravel Pivot Tables - 从反向关系表访问

Question

UPDATE: Apparently $problem->userRatings()->count(); returns 1, so a record does exist, but the script still doesn't enter the foreach loop for some reason...

UPDATE 2/Solution: I feel incredibly foolish, but the reason it isn't working, is that I was calling foreach($problem->userRatings() as $rating){ when it should be foreach($problem->userRatings as $rating){ (dynamic property)

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In my database I have problem_ratings, problems, and users. I have models for users and problems, and problems_ratings is a pivot table between problems and users with an extra 'content' column that stores the numeric rating value (1-5).

The many-to-many relation in my Problem model:

public function userRatings(){
    return $this->belongsToMany('User', 'problem_ratings', 'author_id', 'problem_id')->withPivot('content');
}

The many-to-many relation in my User model:

public function problemRatings(){
    return $this->belongsToMany('Problem', 'problem_ratings', 'author_id', 'problem_id')->withPivot('content');
}

When creating a problem_ratings element, I attach it to my user model like so:

$user->problemRatings()->attach($problem->id, array('content' => $val));

I can access the pivot table through the user, but when I try this:

foreach($problem->userRatings() as $rating){
    echo "In average loop";
    $newAverage = ($rating->pivot->content) + $newAverage;
}

it doesn't find any records, even though some exist in the database. Am I using these relations correctly?

Thanks in advance!

Answer 1

When using a foreach loop over something like this, you need to use dynamic properties (ie. without parentheses):

foreach($problem->userRatings as $rating){ instead of foreach($problem->userRatings() as $rating){