Laravel/Eloquent Relationship Inconsistent - php

Question

I'm trying to get information associated with an application in my database.
Each application has 1 applicant.
Each application has 1 puppy.
I'm returning a view with an eloquent query like this:
$active_applications = Application::with('applicant', 'puppy')->where('kennel_id', '=', $user_kennel->id)->get();
And I have some relationships defined in my application model like so:
public function puppy(){
return $this->belongsTo('App\Puppy');
}
public function applicant(){
return $this->belongsTo('App\User');
}
When the view loads, I'm able to get the information associated with 'puppy'. It retrieves properly. The applicant, however stays null.
I have, in my applications table, a column named "user_id", which I was hoping it would use value in that column to search the users table 'id', and retrieve information on the user. It stays null, however. The following is a dd() of the variable in question:
Am I missing something obvious? Why would it retrieve one and not the other?
EDIT: the puppy table

Answer 1

Your relation is wrong -
public function applicant(){
return $this->belongsTo('App\User');
}
When you don't pass the foreign key as a parameter, laravel looks for the method name + '_id'. Therefore in your case laravel is looking for the column applicant_id in your application table.
So, to get results there are two ways -
1) You need to either change your method name -
public function user(){
return $this->belongsTo('App\User');
}
**2) Pass foreign key as the second parameter - **
public function applicant(){
return $this->belongsTo('App\User', 'user_id');
}
Laravel 5.6 doc - belongsTo
If its a One to Many(Inverse) Relation -
Eloquent determines the default foreign key name by examining the name
of the relationship method and suffixing the method name with a _
followed by the name of the primary key column.
If its a One to One Relation -
Eloquent determines the default foreign key name by examining the name
of the relationship method and suffixing the method name with _id.
Review Laravel doc for more details

Answer 2

Try the following line instead:
$active_applications = Application::with(['applicant', 'puppy'])->where('kennel_id', '=', $user_kennel->id)->get();
As far as I know, multiple "with" should be passed as array.
Adjust the relationship as well
public function applicant(){
return $this->belongsTo('App\User', 'user_id');
}