Im building a website which will have teachers and students. Im using the default Django User models and originally ignored Teachers and treated all my Users as Students. Today I began trying to separate my users into Teachers and Students and am having a lot of difficulty. Im obviously missing some fundamental knowledge and have read a lot online but am going around in circles.
A teacher can have many students and a student can have one teacher.
First I thought Id need separate Student and Teacher models. So everyone now is a User, and I will attach either a Student or Teacher model to each (is this sloppy?).
Now for the relationship. I tried creating a relationship between teachers and students within their own models, but it didnt work so I figured id need a separate TeacherStudentRelationship class to hold the relationships.
This is my implementation so far:
class Student(models.Model):
student = models.OneToOneField(User, on_delete=models.CASCADE)
def __str__(self):
return f'{self.student.username}'
class Teacher(models.Model):
teacher= models.OneToOneField(User, on_delete=models.CASCADE)
def __str__(self):
return f'{self.teacher.username}'
class TeacherStudentRelationship(models.Model):
student = models.ForeignKey(User, on_delete=models.CASCADE)
teacher = models.OneToOneField(User, on_delete=models.CASCADE)
This doesnt throw any errors, though in Django Admin I can create multiple instances of TeacherStudentRelationship and assign a student to a teacher in multiple instances (should only be able to assign a student to a teacher once). I can also only assign a single student to a single teacher within one instance even though the relationship is one-to-many.
I also have a problem with my implementation. I have a signal fire every time a user is created which generates a Student model and links it with the User. This is fine when I have students enrolling on my site, though it means my Admin also needs a Student model (or else it throws errors). I also planned on creating Teachers in the Django Admin panel, but this will cause issues there too as they will need Student models. How would you implement this?
Thank you.
Instead of having a separate relationship like this, you can have a ManyToMany Relation in your teacher model. Like this:
class Student(models.Model):
student = models.OneToOneField(User, on_delete=models.CASCADE)
def __str__(self):
return f'{self.student.username}'
class Teacher(models.Model):
teacher= models.OneToOneField(User, on_delete=models.CASCADE)
students = models.ManyToManyField(Student)
In that way, it won't need to create new student when you are create a Teacher instance or vice versa.
Update
From comments, unfortunately you can't remove signals unless you use custom User model in django. You can try like this:
CHOICES = (('student', "Student"), ('teacher', "Teacher"))
class User(AbstractUser):
user_type = models.CharField(choices=CHOICES, max_length=255)
has_teacher = models.ForeignKey('self', null=True, default=None)
REQUIRED_FIELDS = ['user_type', 'email']
Then, you can define what kind of user it is during the User creating process, hence you do not need the signals. Also, you can store auth data of student and teacher in same model.
Related
I've got a model called Couple. Couple describes the relationship between two Auth.User records.
class Couple(models.Model):
created = models.DateTimeField(auto_now_add=True)
partner_one = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.DO_NOTHING, related_name='partner_one')
partner_two = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.DO_NOTHING, related_name='partner_two')
I'm having trouble referencing the partner in a reliable from their user model because now I need to know which is partner one, partner two. This is obviously not an elegant solution. Is there a better way to achieve what I'm trying to do here?
I'm at a loss... I'm just learning Django and I am really rather confused about how to make a field work the way I would like it to.
I understand that Django has a native "Groups" model. However, I am looking to build my own teams model for customization and practice.
Here is my models.py file for my Users app:
from django.db import models
from django.contrib.auth.models import User
class Team(models.Model):
members = models.ManyToManyField(User)
class Profile(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
admin = models.BooleanField("Admin Status")
Here's where I'm confused. I would like to be able to call the team that the user is part of directly from User.Profile. So, I want to add a field to my Profile class that will automatically populate with the team name when a user is added to a team.
A potential problem I can see is that, currently, I can assign a user to multiple teams. This doesn't bother me, perhaps I can have a Profile model field that automatically populates with a list of all the teams that the user is associated with. Regardless, I can't figure out what type of field I would need to use, or how to do this.
Does that make sense?
A potential problem I can see is that, currently, I can assign a user to multiple teams.
Indeed, you can however easily retrieve the Teams the myprofile object is a member of with:
Team.objects.filter(members__profile=myprofile)
You thus can make a property for the Profile model:
class Profile(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
admin = models.BooleanField("Admin Status")
#property
def teams(self):
return Team.objects.filter(
members__profile=self
)
Then you thus access the Teams of a myprofile with myprofile.teams.
So, I want to add a field to my Profile class that will automatically populate with the team name when a user is added to a team.
From my limited knowledge of database, you can add a name field to your Team model.
Keeping in mind your requirement as mentioned in question, i would suggest you to use django reverse relations to get all the teams the profile is associated with
user_teams = User.objects.get(id='user_id').profile_set.all()[0].team_set.all()
to know more about django ORM reverse relation, here is a very short article
I'm building a project in which I'll have 3 types of users.
Super Admin
Teacher
Student
Teacher and Student will be in a table called Class, each Class will have one teacher and several Student.
As far as I know(Very limited), Django only provide one user table for all kinds of users, But I don't know how to go on, because I will need separated tables to keep the data organized and without redudance, in addition to relate with other tables.
Is there any kind of solution to solve this problem ?
You can implement related_name attributes something similar to this:
from django.contrib.auth.models import User
class ClassRoom(models.Model):
# One classroom one teacher
teacher = models.ForeignKey(User, related_name="teacher")
# One classroom many students
student = models.ManytoManyField(User, blank=True, null=True,
related_name="students")
.....
Also refer to these links for more info:
Django teacher students easy solution. Use separate tables, or permissions and groups? How? Other ideas?
Django model with Foreign Key and ManyToMany relations to same model
Two sets of users (teacher and student) in Django authentication
I'm building a web app to help me manage my classes. So I have a Class model and a Student model and I want each Class to have multiple Students and I want each Student to be able to enroll in multiple Classes:
class Class(models.Model):
name = models.CharField(max_length=30)
enrolled_students = models.ManyToManyField('Student', blank=True)
...
class Student(models.Model):
enrolled_classes = models.ManyToManyField(Class, blank=True)
This works just fine but it's tedious. I create a class and then I create a student and add the enrolled class. And then I have to go BACK into the class and enroll the student. How do I automate this process so that Django automatically keeps track of which students are in which classes and which classes have which students enrolled?
I'm sure there's something simple that I'm missing or not understanding.
There is no need to do this at all. All relationship fields, including many-to-many, automatically add a backwards accessor. Just define the field on one side of the relation; for example, if you define it on Class, you can refer to the classes a student is enrolled in as my_student.class_set.all().
I've read many posts on what OneToOneField, ManyToManyField, and Foreign Key are but they aren't very clear. I am very new to Django and python programming, currently trying to develop models. Can someone explain to me in simple language, preferably with example, what they each are?
Imagine a database, which stores your book collection:
from django.db import models
class Place(models.Model):
address = models.CharField(max_length=50)
country = models.CharField(max_length=50)
class Publisher(models.Model):
name = models.CharField(max_length=30)
place = models.OneToOneField(Place, primary_key=True)
class Author(models.Model):
first_name = models.CharField(max_length=30)
last_name = models.CharField(max_length=40)
class Book(models.Model):
title = models.CharField(max_length=100)
publisher = models.ForeignKey(Publisher)
authors = models.ManyToManyField(Author)
One-to-many/Foreign Key
Every Book has one Publisher, but a Publisher might have published multiple books. Therefore they are in a one-to-many (book-to-publisher) relationship.
One-to-one
Every Publisher is located in one Place, and every Place can only hold one Publisher. Therefore they are in a one-to-one relationship. You could just have well have put the Place information (address and country) with the Publisher model in one table, but sometimes it is preferred to have seperate models. For example, if you do not know the Place for every Publisher, you don't need to take up a lot of space with empty rows.
Many-to-many
Every Book also has one or more Authors. However, an Author might have written multiple Books, so they are in a many-to-many relationship.
If you still need some guidance, I suggest taking a look at the model chapter of the Django Book.