I've got a simple Django photography competition app that has three simple model definitions:
class Person(models.Model):
name = models.CharField(unique=True, max_length=255)
id = models.AutoField(primary_key=True)
class Meta:
db_table = u'people'
def __unicode__(self):
return self.name
class Round(models.Model):
theme = models.CharField(max_length=255)
number = models.IntegerField()
id = models.AutoField(primary_key=True)
class Meta:
db_table = u'rounds'
def __unicode__(self):
return self.season.name+" - "+self.theme
class Entry(models.Model):
rank = int
total_score = models.SmallIntegerField()
id = models.AutoField(primary_key=True)
person = models.ForeignKey(Person, db_column='person')
round = models.ForeignKey(Round, db_column='round')
A Round has multiple Entry objects, and each Entry has one Person. One Person can obviously have multiple Entrys into different Rounds.
In the admin view, I'd like to be able to select a Round and see the details of the Entry items inline. This I can do with the following:
class EntryInline(admin.TabularInline):
model = Entry
fields = ['comments','person','total_score','image']
readonly_fields = ['person','image']
extra = 0
class RoundAdmin(admin.ModelAdmin):
fields = ['theme','number']
inlines = [EntryInline]
However, this sorts the Entry seemingly arbitrarily. I can use django's new ordering keyword in the EntryInline class to specify the ordering should be on the person, but this orders by the person Id property and not their name property.
How would I order this inline on the FK'd Person.name property?
Add this in the EntryInline class:
ordering = ["person__name"]
Related
models.py
class Product(models.Model):
title = models.CharField(max_length=200)
description = models.TextField()
price = models.DecimalField(decimal_places=5,max_digits= 1500)
summary = models.TextField()
featured = models.BooleanField()
def __str__(self):
return self.title
# return f'product title:{self.title}-product price:{self.price}'workok
class Meta:
ordering = ('-price',)
class Opinion(models.Model):
name = models.CharField(max_length=20)
email = models.EmailField(max_length=20)
body = models.TextField()
opinion_date = models.DateTimeField(auto_now_add=True)
active = models.BooleanField(default=False)
product = models.ForeignKey(Product, on_delete=models.CASCADE, related_name='opinion_set')
def __str__(self):
return f'({self.name}) add opinion about ({self.product})'
forms.py:
from django.forms import ModelForm
from .models import Product #space after from keyword
class OpinionModelForm(ModelForm):
class Meta:
model = Product
fields = ['name','email','body','product']
invalid in code line :
fields = ['name','email','body','product'] #---- NOT WORK !!!
, but if i change above code to :
fields = "__all__" # ----it is WORKing ok without any problem !!
question : what is the error? I am not need all the fields in the Product model (like active boolean field), I need only 'name','email','body','product' fields .
According to the error and the code you provided the main problem is that you made a mistake in chosing model in serializer:
class OpinionModelForm(ModelForm):
class Meta:
model = Product
fields = ['name','email','body','product']
Serializer name is OpinionModelForm and listed fields belong to Opinion so I guess you actually wanted to serialize Opinion and no Product as you defined at this line:
model = Product
Simply change it to:
model = Opinion
Looking for solution of this problem I encountered some similar threads, but referring to older versions of Django/DRF and thus not working in my case.
There are these two models:
class CsdModel(models.Model):
model_id = models.CharField("Item ID", max_length=8, primary_key=True)
name = models.CharField("Item Name", max_length=40)
active = models.BooleanField(default=True)
def __str__(self):
return self.model_id
class CsdListing(models.Model):
model_id = models.ForeignKey(CsdModel, on_delete=models.CASCADE, default=0, related_name='m_id')
name = models.ForeignKey(CsdModel, on_delete=models.CASCADE, default=0, related_name='m_name')
(...)
EDIT: Serializers are defined this way:
class CsdModelSerializer(serializers.ModelSerializer):
model_id = serializers.RegexField(regex='^\w{2}\d{3}$', allow_blank=False)
name = serializers.CharField(min_length=6, max_length=50, allow_blank=False)
class Meta:
model = CsdModel
fields = '__all__'
class CsdListingSerializer(serializers.ModelSerializer):
session_id = serializers.RegexField(regex='^s\d{2}$', allow_blank=False)
def validate_session_id(self, value):
(...)
class Meta:
model = CsdListing
fields = '__all__'
What I'd like to see, is model_id and name from CsdModel displayed inside a form created based on CsdListing model. But instead, the ID is duplicated:
How should I rebuild the model(s) to have both ID and name displayed in the form?
You should have only one foreign key. But the listing serializer should then reference the model as a nested serializer.
class CsdListing(models.Model):
model = models.ForeignKey(CsdModel, on_delete=models.CASCADE, default=0, related_name='listing')
class CsdListingSerializer(serializers.ModelSerializer):
model = CsdModelSerializer()
session_id = serializers.RegexField(regex='^s\d{2}$', allow_blank=False)
I am trying to accomplish something very similar to:
How to join 3 tables in query with Django
Essentially, I have 3 tables. In the Django REST we are showing table 3. As you see below (models.py), table 3 has company_name which is a foreign key of table 2 and table 2 is a foreign key of table 1. Both table 2 and 3 are linked by the table 1 ID. Table 1 contains the actual text, which we want to display in the API output, not the ID number.
Table 1: Manufacturer of Car -- Table 2: What the Car is -- Table 3: list of all cars
Models.py
Table 1:
class ManufacturerName(models.Model):
name_id = models.AutoField(primary_key=True)
company_name = models.CharField(unique=True, max_length=50)
class Meta:
managed = False
db_table = 'manufacturer_name'
Table 2:
class CarBuild(models.Model):
car_id = models.AutoField(primary_key=True)
car_icon = models.CharField(max_length=150, blank=True, null=True)
company_name = models.ForeignKey('ManufacturerName', models.DO_NOTHING, db_column='ManufacturerName')
class Meta:
managed = False
db_table = 'car_build'
Table 3:
class CarList(models.Model):
list_id = models.AutoField(primary_key=True)
company_name = models.ForeignKey('CarBuild', models.DO_NOTHING, db_column='CarBuild')
title = models.CharField(unique=True, max_length=100)
description = models.TextField()
class Meta:
managed = False
db_table = 'cars'
Within my views:
This is what I am trying, based on the foreign key relationships:
queryset = CarList.objects.all().select_related('company_name__company_name')
I get no errors when I save and run this, however, the ID is still being returned, and not the text associated with the foreign key relationships:
[
{
"list_id": 1,
"company_name": "http://127.0.0.1:8000/api/1/",
"title": "Really fast car you're driving, and this is dummy text",
Again, I would like to achieve getting the text associated with the company_name foreign key relationships from table 1 to show in the JSON.
serializer and viewset
class manufacturer_name(serializers.HyperlinkedModelSerializer):
class Meta:
model = manufacturer_name
fields = ('name_id', 'company_name')
class manufacturer_name(viewsets.ModelViewSet):
queryset = manufacturer_namee.objects.all()
serializer_class = manufacturer_name
class CarBuildViewSet(viewsets.ModelViewSet):
queryset = CarBuild.objects.all()
serializer_class = CarBuildSerialiser
class CarBuildSerialiser(serializers.HyperlinkedModelSerializer):
class Meta:
model = CarBuild
fields = ('car_id', 'car_icon', 'company_name')
class CarListSerialiser(serializers.HyperlinkedModelSerializer):
class Meta:
model = News
fields = ('list_id', 'company_name', 'title')
class CarListViewSet(viewsets.ModelViewSet):
serializer_class = CarList
def get_queryset(self):
queryset = News.objects.all().select_related('company_name__company_name')
return queryset
Based on detailed conversation to clear few details. Here is the answer.
You need to make small changes to your models as it was quite confusing to understand what you want to achieve.
Models:
class ManufacturerName(models.Model):
name_id = models.AutoField(primary_key=True)
company_name = models.CharField(unique=True, max_length=50)
class Meta:
managed = False
db_table = 'manufacturer_name'
class CarBuild(models.Model):
car_id = models.AutoField(primary_key=True)
car_icon = models.CharField(max_length=150, blank=True, null=True)
manufacturer = models.ForeignKey(ManufacturerName,on_delete=models.SET_NULL)
class Meta:
managed = False
db_table = 'car_build'
class CarList(models.Model):
list_id = models.AutoField(primary_key=True)
car = models.ForeignKey(CarBuild, on_delete=models.DO_NOTHING)
title = models.CharField(unique=True, max_length=100)
description = models.TextField()
class Meta:
managed = False
db_table = 'cars'
And then You need to adjust your serializers.
class CarListSerialiser(serializers.HyperlinkedModelSerializer):
company_name= serializers.SerializerMethodField(read_only=True)
class Meta:
model = CarList
fields = ('list_id', 'company_name', 'title')
def get_company_name(self, obj):
return obj.car.manufacturer.company_name
And you use it in your view:
class CarListViewSet(viewsets.ModelViewSet):
queryset = CarList.object.all()
serializer_class = CarListSerialiser
I have the following models:
class Category(models.Model):
name = models.CharField()
... # fields omitted
class Prediction(models.Model):
conversation = models.ForeignKey(Conversation)
category = models.ForeignKey(Category)
... # fields omitted
class Conversation(models.Model):
sid = models.CharField()
... # fields omitted
Now I'm trying to create a model serializer for Category that would return me the following serialized object:
{
"name":"blah",
"conversations":[
"2af22188c5c97256", # This is the value of the sid field
"073aef6aad0883f8",
"5d3dc73fc8cf34be",
]
}
Here is what I have in my serializer:
class CategorySerializer(serializers.ModelSerializer):
conversations = serializers.SlugRelatedField(many=True,
read_only=True,
source="prediction_set",
slug_field='conversation.sid')
class Meta:
model = models.Class
fields = ('class_name', 'conversations')
However, this doesn't work because somehow django doesn't allow me to set slug_field to be a field that's within an object field. Any suggestions on how to accomplish this?
You are modelling a Many-to-Many relationship between Categorys and Conversations with a explicit table called Prediction. The django way of doing this would be to explicitly state the Many-to-Many on either side of the relationship and specify Prediction as the "through-model":
Shamelessly stolen example from this question:
class Category(models.Model):
name = models.CharField(max_length=255)
slug = models.SlugField(unique=True, max_length=255, blank=True,default=None)
desc = models.TextField(blank=True, null=True )
...
class Post(models.Model):
title = models.CharField(max_length=255)
pub_date = models.DateTimeField(editable=False,blank=True)
author = models.ForeignKey(User, null=True, blank=True)
categories = models.ManyToManyField(Category, blank=True, through='CatToPost')
...
class CatToPost(models.Model):
post = models.ForeignKey(Post)
category = models.ForeignKey(Category)
...
This shows a good way to set up the relationship.
Equally shamelessly stolen from the answer by #Amir Masnouri:
class CategorySerializer(serializers.ModelSerializer):
class Meta:
model = Category
fields = ('name','slug')
class PostSerializer(serializers.ModelSerializer):
class Meta:
model = Post
fields = ('id','{anything you want}','categories')
depth = 2
This shows a nice way of achieving the nested serialization behavior that you would like.
As stated in the title how does manytomanyfield with through appear in the admin site?
class SchoolClass(models.Model):
id = models.AutoField(primary_key = True)
class_name = models.TextField()
level = models.IntegerField()
taught_by = models.ManyToManyField(User,related_name="teacher_teaching",through='TeachSubject')
attended_by = models.ManyToManyField(User,related_name='student_attending')
def __unicode__(self):
return self.class_name
class Meta:
db_table = 'classes'
class TeachSubject(models.Model):
teacher = models.ForeignKey(User)
class_id = models.ForeignKey(SchoolClass)
subject = models.ForeignKey(Subject)
In the admin site, for the model SchoolClass, I have a field for attending students, but not the teachers.
You should use InlineModelAdmin. Docs.
class TeachSubjectInline(admin.TabularInline):
model = TeachSubject
extra = 2 # how many rows to show
class SchoolClassAdmin(admin.ModelAdmin):
inlines = (TeachSubjectInline,)
admin.site.register(SchoolClass, SchoolClassAdmin)