Hello I am working on a Laravel project, that i have to assign for one Mentorship «Mentoria», one Mentor «Mentor» and one student «Mentorando». The data of the student and the mentor, came from the Users table (i assigned them roles, using Spatie) , and the other table is called «Mentoria» Since there exists a many to many relation i created the pivot table that is called «utilizador_mentoria» and has ID_Mentor, ID_Mentorando (both are FKs coming from the users table),and ID_mentoria (coming from Mentoria table). I defined both models as this:
User Model:
''' protected $casts = [
'email_verified_at' => 'datetime',
];
public function interesses(){
return $this->belongsToMany(AreaInteresse::class, 'utilizador_interesse', 'id_utilizador', 'id_interesse');
}
public function mentorias(){
return $this->belongsToMany(Mentoria::class, 'utilizador_mentoria', 'id_mentoria', 'id_mentorando', 'id_mentor');
} '''
ps: I have interesses function with other model, that is working properly. my problem is with the «mentorias»
Mentoria Model:
''' public function users(){
return $this->belongsToMany(User::class, 'utilizador_mentoria','id_mentor','id_mentorando','id_mentoria');
}'''
With this, i am trying to get the data from all Mentorias, and the data of the Mentor that is assigned to that that Mentoria, however when i am doing this code on the controller, the data coming from the user appears empty, despite i have the DB filled with data. I tried a echo for testing, and it only shows the data of the Mentoria, and where it should appear the data of the Mentor assigned to that MEntoria, it is empty
the code from the controller:
'''public function mentorias(){
$mentorias = Mentoria::with('users')->get();
echo $mentorias;
return view('admin/mentorias/admin_mentorias', ['mentorias' => $mentorias]);
}'''
the output of the echo
'''[{"id":2,"titulo":"teste","titulo_en":"test","descricao":"fe","descricao_en":"ewfwe","created_at":"2021-12-28T01:32:10.000000Z","updated_at":"2021-12-28T01:32:10.000000Z","users":[]}]'
Since as i already said, i already used data from 2 tables with Many to Many relation, however with only 1 FK per PK, and it is working properly, i have no idea why it is not working this way . I already checked for similar questions, however with no luck
Thank You
Edit:
For testing purposes, i removed the column of one of the two FK that reference from the same PK, and i managed to work, however with this aditional FK i am not managing to make it work . I believe that the problem is with the relation, in the models but i have no idea how to make it work
I rearranged the funcitons in the models as they are now User Model: ''' public function mentorias(){ return $this->belongsToMany(Mentoria::class, 'utilizador_mentoria', 'id_mentor', 'id_mentorando', 'id_mentoria'); } '''
Mentoria Model:
''' public function users(){ return $this->belongsToMany(User::class, 'utilizador_mentoria','id_mentoria','id_mentorando','id_mentor'); '''
i also tried to took out,example «id_entorando» from the main () and put it after with the «withPivot» method, but it still didn't worked
CodePudding user response：
I don't know if I properly understood the problem but your relationship is not a single "many to many", but two "one to many". In the end I'll show why it's convenient to consider them as two separated relationships.
First: If a user can have multiple mentorships but a mentorship can have only 1 mentor (which I suppose is what's happening), then you should use the "hasMany/belongsTo" pair:
User Model:
public function mentorias(){
return $this->hasMany(Mentoria::class);
}
Mentoria Model:
public function user(){
return $this->belongsTo(User::class);
}
Second: Complete the scenario with the other relationship bewteen the mentorship and the students:
User Model:
public function mentorias(){
return $this->hasMany(Mentoria::class);
}
public function mentoria(){
return $this->belongsTo(Mentoria::class);
}
Mentoria Model:
public function user(){
return $this->belongsTo(User::class);
}
public function mentorandos(){
return $this->hasMany(User::class);
}
There should be a user_id column in the mentorias table that represents the Teacher which the mentorships belong to:
Schema::table('mentorias', function (Blueprint $table) {
$table->unsignedInteger('user_id')->nullable();
});
And there should also be a mentor_id column in the users table that represents the mentorship which the students belong to:
Schema::table('users', function (Blueprint $table) {
$table->unsignedInteger('mentoria_id')->nullable();
});
Third: This double representation of the User Model could lead to confusion, since two different objects (teacher and student) are using the same model but are not meant to have both relationships simultaneously: A teacher shouldn't be mentored and a student shouldn't lead mentorships.
In order to roperly manage Teachers and Students and prevent confusion, you could create additional models that inherit the User Model and define the relationships for them (instead of the User Model), so you can limit the fields and the relationships for each one of them.
User Model:
// No relationships
Teacher Model:
// Extending from User allows you to have all the User Model functionality
class Teacher extends User
{
public function mentorias(){
return $this->hasMany(Mentoria::class)->with('students');
}
}
Student Model:
// Extending from User allows you to have all the User Model functionality
class Student extends User
{
public function mentoria(){
return $this->belongsTo(Mentoria::class)->with('teacher');
}
}
Mentoria Model:
public function teacher(){
return $this->belongsTo(Teacher::class);
}
public function students(){
return $this->hasMany(Student::class);
}
In the end, you'll have all the info you need from the mentorship when you call objects like this:
Teacher::with('mentorias')->get();
// This will show the Teacher's mentorias and the students in each one
Student::with('mentoria')->get();
// This will show the Student's mentoria and its teacher
Mentoria::with(['teacher', 'students'])->get();
// This will show the teacher and the students for each mentoria