Now I'm working with python django.
I have derived a Model class from user:
from django.contrib.auth.models import User
class Customer(User):
mobile = models.CharField(max_length=14)
class Meta:
db_table = 'customer_user'
Question
Now comes the question, I have some normal user object, which is not yet a CustomerUser object.
>>> john = User.objects.get(username='john')
>>> hasattr(john.customer)
False
Infact the john object has a row in the user table in database, but has no row in the customer table.
I want to change john into a Customer object, i.e. adding a row of customer, pointing the parent link to the initial user object row.
I tried the following code, but did not work?
>>> Customer.objects.create(user=john, mobile='1234')
Is there any nice way to do the job?
You have two options, as described in the documentation:
1. Make your Customer model a proxy for the User model:
class Customer(User):
class Meta:
proxy = True
Then any instance of User is also an instance of Customer. Note that you probably don't want to set a custom table_name in this case because both models operate through the same table.
2. Make your Customer a profile model that has a one-to-one relationship with the core User model:
from django.contrib.auth.models import User
class Customer(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
mobile = models.CharField(max_length=14)
Then:
john = User.objects.get(username='john')
if not hasattr(john, 'customer'):
Customer.objects.create(user=john, mobile='1234')
The second approach seems to me to be a better fit for your use case.
Related
I want to extend the Base Abstract User Model and this is the extended model:
class Student(AbstractUser):
birth = models.DateField(default=datetime.date.today)
street = models.CharField(max_length=25)
street_number = models.IntegerField(validators=[MinValueValidator(0), MaxValueValidator(99)])
city = models.CharField(max_length=20)
province = models.CharField(max_length=20)
code = models.IntegerField(validators=[MinValueValidator(0, MaxValueValidator(9999))])
address = str(street) + str(street_number) + str(city) + str(code) + str(province)
But I get this message popup:
It is impossible to add a non-nullable field 'password' to student without specifying a default. This is because the database needs something to populate existing rows.
However I haven't added a new password field and all the existing password fields (for the superuser) already have a value. What should I do?
When I add a default value and try to migrate it, it complains that there is no such table as 'mainApp_student'.
You don't want to do that. You want a User model (you already have one that Django provides, no need to extend it for now), and a Student model that has a OneToOne relationship with the User model.
Conceptually:
User: models a user of your application and its authentication and permissions
Student: the representation of a person attending classes, with a name, a birthday etc..., also has a user to access your application which is unique to them.
In code:
from django.db import models
from django.contrib.auth.models import User
class Student(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE))
# ... other fields: birth address etc...
This page of the docs explains it well, especially the Employee example given:
If you wish to store information related to User, you can use a OneToOneField to a model containing the fields for additional information. This one-to-one model is often called a profile model, as it might store non-auth related information about a site user.
I'm making one of my first django apps with sqlite database. I have some models like for example:
class Connection(models.Model):
routeID = models.ForeignKey(Route, on_delete=models.CASCADE)
activityStatus = models.BooleanField()
car = models.ForeignKey(Car, on_delete=models.CASCADE)
class Route(models.Model):
name = models.CharField(max_length=20)
and forms
class RouteForm(ModelForm):
class Meta:
model = Route
fields = ['name']
class ConnectionForm(ModelForm):
class Meta:
model = Connection
fields = ['routeID', 'activityStatus', 'car']
And in my website, in the url for adding new Connection, I have cascade list containing RouteIDs. And I'd like it to contain RouteName, not ID, so it would be easier to choose. How should I change my ConnectionForm, so I could still use foreign key to Route table, but see RouteName instead of RouteID?
For now it's looking like this, but I'd love to have list of RouteNames, while still adding to Connection table good foreign key, RouteID
Update the Route Model's __str__ method:
class Route(models.Model):
name = models.CharField(max_length=20)
def __str__(self):
return self.name
Because the __str__() method is called whenever you call str() on an object. Django uses str(obj) in a number of places like in Modelform. By default it returns id or pk that is why you were seeing ids in model form. So by overriding it with name, you will see the names appear in choice field. Please see the documentation for more details on this.
So I have been searching all around the internet for a full example of how to user AbstractUser when u have at least 2 different models. Didn't find anything conclusive.. at least that would work on latest version of Django (2.0.1).
I have 2 models, teacher and student, and registration needs to be different. Besides username, email, name and surname, I need for example, for the student, to upload a profile picture, email, phone, student_ID. And for teacher, bio, academic title and website. Did I start good ? What is the right approach ?
class Profile(AbstractUser):
photo = models.ImageField(upload_to='students_images')
email = models.EmailField()
phone = models.CharField(max_length=15, )
class Student(Profile):
student_ID = models.CharField(unique=True, max_length=14,
validators=[RegexValidator(regex='^.{14}$',
message='The ID needs to be 14 characters long.')])
def __str__(self):
return self.name
class Teacher(Profile):
academic_title = models.CharField(max_length=30)
bio = models.TextField()
website = models.URLField(help_text="E.g.: https://www.example.com", blank=True)
Your goals can be accomplished using a 'Profile' pattern. You don't necessarily need to use a custom user model for this. But you need to have a single common model to for authentication; you can use the builtin django user for this or a custom class... Your Student and Teacher models should be OnetoOne relationships. This is the recommended solution per the documentation.
If you wish to store information related to User, you can use a OneToOneField to a model containing the fields for additional information. This one-to-one model is often called a profile model, as it might store non-auth related information about a site user.
In your case, you may do something like this:
class StudentProfile(models.Model):
user = models.OneToOneField('User', related_name='student_profile')
# additional fields for students
class TeacherProfile(models.Model):
user = models.OneToOneField('User', related_name='teacher_profile')
# additional fields for teachers
Then you can create your registration forms based on these profile models.
class StudentResistrationForm(forms.ModelForm):
class Meta:
model = StudentProfile
fields = (...)
class TeacherRegistrationForm(forms.ModelForm):
class Meta:
model = TeacherProfile
fields = (...)
You can create the user instance to which the profile is related to at the same time you create the profile. You might do this with formsets, for example.
add
class Meta:
abstract = True
to profile model
and change AbstractUser to models.Model
I would like to define a django model which has many-to-one relationship with itself. It is a user profile, connected as a OneToOne field with the authentication user model. I would like to save which user (if any) was the one who referred the 'current' user to my system. This means I have the following definition:
class UserProfile(models.Model):
user = models.OneToOneField(User, blank=True, related_name='profile')
class Meta:
abstract = True
class SpecificUserProfile(UserProfile):
referrer = models.ForeignKey('self')
I saw the django defaults to naming the set of referenced models by the name of the class with a suffix _set. I believe I will be getting something along the lines of specific_user_profile_set. I would much prefer to have it named u1.referrer and u2.referred or u2.referred_set. Is there any way this can be achieved?
related_name='profile'
This is the argument to define a name for any related field, so:
class SpecificUserProfile(UserProfile):
referrer = models.ForeignKey('self', related_name='referred')
I am using Django Rest Framework to provide API to a mobile app. I have two models, Order and User. Order has a foreign key relation to User.
For about 1% or so of all my order objects, the User field is null. I've been testing this behavior using cURL.
If I do a cURL without a user object, it tells me "This field is required".
If done with a wrong user object, it tells me that the object does not exist. Both of these are the intended and expected behaviors.
I'm trying to figure out how it is possible for some of the Order objects to be saved without a user field. Is there something I'm not taking into account?
My views:
class OrderList (generics.ListCreateAPIView):
model = Order
serializer_class = OrderSerializer
And serializer:
class OrderSerializer (serializers.ModelSerializer):
user = serializers.SlugRelatedField(slug_field = 'user')
partial = True
class Meta:
model = Order
Models:
class User (models.Model):
uid = models.CharField(max_length =200, unique=True)
class Order (models.Model):
uid = models.ForeignKey (User, related_name = "orders", verbose_name = "User",blank=True, null=True)
You could use two different ModelSerializer classes, one for creation, that makes sure, that an Order object can't be created without a related User and one for updating orders, that passes required=False to the related field's constructor, so that you still can save existing orders that haven't a related User.
Try adding default=None to your models.ForeignKey declaration. You could also just create an anonymous user in the users table and when the user isn't specified it could set the anonymous user instead.