Laravel Hasmanythrough relationship with 'where' clause not returning expected results

I'm working on a Laravel application where I have a complex relationship between CourseUser (extended by an Applicant model), User, and UserEducation models. I'm trying to set up a hasManyThrough relationship that also filters based on the course_id of the CourseUser/Applicant model.

public function userEducations()
{
    return $this->hasManyThrough(
        UserEducation::class,
        User::class,
        'id',
        'user_id',
        'user_id',
        'id'
    )->where('user_education.course_id', $this->course_id);
}

The issue is that this relationship is not returning any data when it should. Interestingly, if I remove the where clause from the relationship definition and apply it manually when querying, it works:

$applicant->education()->where('user_education.course_id', $applicant->course_id)

here is how i load the releationship

$applicant->load(['user','course.program','country','city','languages','education','leadership']);

LaryAI

1 year ago

Level 58

The issue you're encountering is likely due to the way the where clause is being applied in the hasManyThrough relationship. When you define a relationship in Laravel, the where clause is applied at the time of relationship definition, which might not have access to the dynamic context (like $this->course_id) you expect.

To solve this, you can use a closure to define the relationship and apply the where clause dynamically when querying. Here's how you can adjust your userEducations method:

public function userEducations()
{
    return $this->hasManyThrough(
        UserEducation::class,
        User::class,
        'id', // Foreign key on the User table...
        'user_id', // Foreign key on the UserEducation table...
        'user_id', // Local key on the Applicant table...
        'id' // Local key on the User table...
    );
}

// When querying, apply the where clause dynamically
public function getUserEducations()
{
    return $this->userEducations()->where('user_education.course_id', $this->course_id)->get();
}

Then, when you want to load the relationship with the condition, you can use the getUserEducations method:

$applicant->load(['user', 'course.program', 'country', 'city', 'languages', 'leadership']);
$educations = $applicant->getUserEducations();

This approach separates the relationship definition from the query logic, allowing you to apply dynamic conditions when you actually perform the query.

KhaledS

1 year ago

Level 3

i did think of this solution but

The Applicant model logically belongs to a single course, but this userEducation relationship returns the education records of different applicants who belong to the same user. This breaks the logical consistency.

To maintain this consistency, I want the relationship itself to return only the UserEducation records specific to the current applicant and their course, without needing to write a custom query scope.

its more about maintaining clean code and releationships that logically hold

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