Fetching data from models using OneToOneField in Django-CodePudding

well my college is making us go learn a framework and make a website with it in a month, and it's really killing me, because of that I couldn't really get a good understanding of the Django framework as I am making progress while watching YouTube vids and reading docs. Anyways my models are all messed up which made the job even harder, and whenever I solve a problem another one arises, but the deadline is close and making any changes to the models will cost me a great deal of time. This time my problem is about fetching data. The concerned models are the following:

The User class for authentication

class User(AbstractBaseUser, PermissionsMixin):
    id = models.AutoField(primary_key=True,null=False)
    username = models.CharField(max_length=50)
    email = models.EmailField(unique=True)
    nom = models.CharField(max_length=255)
    prenom = models.CharField(max_length=255)
    usertype = models.CharField(choices=types,max_length=20,default="user")
    date_joined = models.DateTimeField(auto_now_add=True)
    last_login = models.DateTimeField(auto_now=True)
    is_superuser = models.BooleanField(default=False)
    is_staff = models.BooleanField(default=False)
    is_active = models.BooleanField(default=True)
    student_data = models.OneToOneField(Etudiant, on_delete=models.CASCADE,blank=True, null=True,related_name='Etudiant_access')
    Prof_data = models.OneToOneField(Prof, on_delete=models.CASCADE,blank=True, null=True)
    objects=UserManager()

    def __str__(self):
        return  self.prenom   " "   self.nom 

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['username']

The Students(Etudiant) class for managing the students:

class Etudiant(models.Model):
    filiere = models.ForeignKey(Filiere, on_delete=models.DO_NOTHING)
    classe = models.ForeignKey(Classe,null=True, on_delete=models.DO_NOTHING)
    notes = models.ManyToManyField(note,blank=True, null=True)

The class Classe (LMAO) for managing the different classes:

class Classe(models.Model):
    #Cla_id = models.AutoField(primary_key=True, null=False)
    Designation = models.CharField(max_length=100)
    filiere = models.ForeignKey(Filiere, on_delete=models.CASCADE)
    Epreuve = models.ManyToManyField(Epreuve,blank=True, null=True)
    def __str__(self):
        return self.Designation

The thing is that I wanna fetch all data of the Users that are students (which means that their Prof_data attribute is blank/null and their student_data attribute is pointing to the Etudiant(Student) class while having an Etudiant.classe attribute equals to a value in the view's parameters

I've solved a great deal of it but I'm stuck at the end This is my view function:

@login_required
def class_info(request,design):
    
#getting the Classe(s) from the url which Designation == design
    classe_now = Classe.objects.get(Designation=design)
    print(classe_now) # This works like a charm
    
#getting the Students objects that are part of the class_now
    Etudiants = Etudiant.objects.filter(classe=classe_now)
    print(Etudiants) # This works too. It returns the 'Etudiant' objects from where i wanna access to the Users data
    
#getting the User data of the student objects (This is where i get confused)
    students_to_show = User.objects.filter(student_data=Etudiants)
    pprint(students_to_show)
    
    return render(request, 'Prof/class_info.html')

I am really confused, you are truly my last hope in this, and thank you for your time.

CodePudding user response：

You can filter your User model by selecting all users that do have empty/null relation to Prof model and nonempty/null relation to Etudiant model.

student_users = User.objects.filter(Prof_data__isnull=True, student_data__isnull=False)

then for each stident_user, you can fetch its student data in the following manner:

student_user = student_users[0]
student_user.student_data.filiere
student_user.student_data.classe
student_user.student_data.notes

You can then pass the queryset result to the render function as a context variable. Check this brief tutorial on how to pass data to templates.