Laravel 5.4-几个表中的多个关系

Question

In a picture below we can see relations between my tables. My target is to get " type " from driver_license_types . Starting at user object. For example:

$user = User::find(1);

and from there I need to get type from driver_license_types. Important thing is that instructors can have few records in instructor_license_types table, like this:

My current solutions:

• In User model I create method instructor which is relation "belongTo" instructor model.
• in Instructor model I created method license which is relation "hasMany" with Instructor_license_types
• In Instructor_license_types, I create method types which is relation "hasMany" with Driver_license_types.

And final code look like:

Is there any better solutions?

Answer 1

You can get the driver_license_types directly from the Instructors model by adding this function:

//PathToModel\Instructor.php

public function license_types()
{
    return $this->belongsToMany('PathToModel\LicenseTypes', 'instructors_license_types');
}

Also add this to the LicenseType model:

//PathToModel\LicenseTypes.php

public function instructors()
{
    return $this->belongsToMany('PathToModel\Instructors', 'instructors_license_types');
}

This way you will be able to remove one of your foreach statements in your code:

$user = User::find($id);
if($user->instructor){
    $tmp = [];
    foreach ($user->instructor->license_types as $data) {
        array_push($tmp, [$data->id, $data->type]);
    }
    $user->types = $tmp;
}

What this does is just skips over the pivot table (instructos_license_types), for more info on this you can see docs here .

Answer 2

If you don't have belongsToMany relationship set up in your Instructor model for DriverLicenseType I would suggest putting one in:

public function licenseTypes()
{
    return $this->belongsToMany(DriverLicenseType::class, 'instructors_license_types', 'instructor_id', 'driver_license_type_id');
}

$user = User::find(1);

$licenseTypes = $user->instructor->licenseTypes->pluck('type')->unique();

or if you need the $licenseTypes to be in the format you have in your question you could do something like:

$licenseTypes = $user->instructor->licenseTypes->map(function ($item) {
    return [$item->id, $item->type];
});