I can't find a valid way with Django OMR in order to get : ( a raw query is also fine )
the Sites.sitename which made the Analysis where (Analysi_Items.name='somename' and Analysis_Items.value='somevalue') and (Analysi_items_name='somename' and Analysis_Items.value='somevalue') and (Analysis_items.name='somename' and Analysis_Items.value='somevalue').
class Sites(models.Model):
region = models.CharField(max_length=1000)
province = models.CharField(max_length=1000)
sitename = models.CharField(max_length=1000, primary_key=True)
class Meta:
verbose_name_plural = "Sites"
def __unicode__(self):
return self.sitename
class Analysis_Items(models.Model):
code = models.ForeignKey('Analysis')
name = models.CharField(max_lenght=100)
value = models.CharField(max_length=20)
class Meta:
verbose_name_plural = "Analysis Type"
class Analysis(models.Model):
date = models.DateField()
site = models.ForeignKey('Sites')
def __unicode__(self):
return str(self.date)
class Meta:
verbose_name_plural = "Analysis"
Hope this is clear enough. thank you in advance!
Site.objects.filter(analysis__analysis_items__name='some_name', analysis__analysis_items__value='some_value')
You can keep adding additional parameters in the same keep AND'ing them all together.
Related
SerializerClass:
class VacancySerializer(serializers.ModelSerializer):
organization_small_name = serializers.CharField(source='organization.short_name', read_only=True)
class Meta:
model = Vacancy
fields = ['organization', 'description', 'specs', 'type', 'publication_date',
'is_published', 'withdrawal_data', 'organization_small_name', ]
read_only_fields = ['publication_date', 'is_published', 'withdrawal_data',]
ViewSet:
class VacancyViewSet(viewsets.ModelViewSet):
queryset = Vacancy.objects.all()
serializer_class = VacancySerializer
filter_backends = [filters.SearchFilter]
search_fields = ['organization_small_name']
...
Model:
class Vacancy(models.Model):
organization = models.OneToOneField(DictOrganization, on_delete=models.CASCADE, related_name='vacancies')
description = models.TextField('Описание')
specs = models.ManyToManyField(DictSpec, blank=True)
type = models.CharField('Тип', max_length=20, choices=VacancyType.choices(), default=VacancyType.PRACTICE.value)
publication_date = models.DateField('Дата публикации', null=True, blank=True)
is_published = models.BooleanField('Опубликовано', default=False)
withdrawal_data = models.DateField('Дата снятия с публикации', null=True, blank=True)
My goal is to make API search by 'organization_small_name' field
that is in VacancySerializer.
Server runs successfully, but as soon as i add ?search parameter, i get next error:
Why it doesn't recognize 'organization_small_name' field, even thought it is decribed in serializer, and how can i fix it?
Relatively new to Django and I have the following models in my django (3.2) project:
class projectsA(models.Model):
projectID_A = models.BigIntegerField(primary_key=True)
project_name_A = models.TextField(blank=True, null=True)
project_desc_A = models.TextField(blank=True, null=True)
projectID_B = models.ForeignKey('projectsB', models.DO_NOTHING, db_column='projectID_B', blank=True, null=True, db_constraint=False)
class Meta:
managed = False
db_table = 'projectsA'
class projectsB(models.Model):
projectID_B = models.BigIntegerField(primary_key=True)
project_name_B = models.TextField(blank=True, null=True)
project_desc_A = models.TextField(blank=True, null=True)
class Meta:
managed = False
db_table = 'projectsB'
I want to get all projects from projectsA which are not in projectsB. The SQL equivalent would be
SELECT * FROM projectsA a LEFT JOIN projectsB b on a.projektID_B = b.projectID_B WHERE b.projectID_B is null
I have tried with .exclude or .select_related() and several other approaches, but cannot find a solution for this scenario. Thanks in advance.
It should be something like:
queryset = projectsA.objects.filter(projektID_B__isnull=True)
You can read about isnull here https://docs.djangoproject.com/en/4.0/ref/models/querysets/#isnull
I'm trying to build an api that have an endpoint which in the POST receives the JSON like bellow:
{
"title":"Quiz 1",
"questions":[
{
"description":"Question 1?",
"answers":[
{
"description":"Answer 1",
"true_or_false":true
},
{
"description":"Answer 2",
"true_or_false":false
}
]
},
{
"description":"Question 2?",
"answers":[
{
"description":"Answer 1",
"true_or_false":true
},
{
"description":"Answer 2",
"true_or_false":false
}
]
}
]
}
But I don't know how to build the serializers for double nested fields, like a list of answers within a question and a list of questions within a quiz. The code I made so far is below:
models.py
from django.db import models
class Quiz(models.Model):
title = models.CharField(max_length=200, blank=False)
def __str__(self):
return self.title
class Question(models.Model):
description = models.CharField(max_length=10000, blank=False)
quiz = models.ForeignKey(Quiz, related_name='questions', on_delete=models.CASCADE, default=None)
def __str__(self):
return self.description
class Answer(models.Model):
question = models.ForeignKey(Question, related_name='answers', on_delete=models.CASCADE)
description = models.CharField(max_length=1000, blank=False)
true_or_false = models.BooleanField(default=False, blank=False)
def __str__(self):
return self.description
views.py
class QuestionViewSet(viewsets.ModelViewSet):
queryset = Question.objects.all()
serializer_class = QuestionSerializer
class AnswerViewSet(viewsets.ModelViewSet):
queryset = Answer.objects.all()
serializer_class = AnswerSerializer
class QuizViewSet(viewsets.ModelViewSet):
queryset = Quiz.objects.all()
serializer_class = QuizSerializer
class OnlyQuizViewSet(generics.ListAPIView):
def get_queryset(self):
queryset = Quiz.objects.filter(id=self.kwargs['pk'])
return queryset
serializer_class = QuizSerializer
serializers.py
class AnswerSerializer(serializers.ModelSerializer):
class Meta:
model = Answer
fields = ['id', 'description', 'true_or_false']
class QuestionSerializer(serializers.ModelSerializer):
answers = AnswerSerializer(many=True)
class Meta:
model = Question
fields = ['id','description','answers']
read_only_fields = ('quiz',)
def create(self, validated_data):
answers_data = validated_data.pop('answers')
question = Question.objects.create(**validated_data)
for answer in answers_data:
Answer.objects.create(question=question, **answer)
return question
class QuizSerializer(serializers.ModelSerializer):
questions = QuestionSerializer(many=True)
class Meta:
model = Quiz
fields = ['id', 'title', 'questions']
def create(self, validated_data):
questions_data = validated_data.pop('questions')
quiz = Quiz.objects.create(**validated_data)
for questions in questions_data:
Question.objects.create(quiz=quiz, **questions)
return quiz
With the above serializers, I'm getting the error below:
Direct assignment to the reverse side of a related set is prohibited. Use answers.set() instead.
So what's the right way to build double-nested serializers? So far I haven't been able to find anything to help me
I'm gonna assume you get that error when you try posting to the Quiz api, you'll have a problem when you want to create a question
Question.objects.create(quiz=quiz, **questions)
since this question also includes a list of answers that needs to be created first.
Try using the serializer you already have like this
class QuizSerializer(serializers.ModelSerializer):
questions = QuestionSerializer(many=True)
class Meta:
model = Quiz
fields = ['id', 'title', 'questions']
def create(self, validated_data):
questions_data = validated_data.pop('questions')
quiz = Quiz.objects.create(**validated_data)
for questions in questions_data:
question_serializer = QuestionSerializer({**questions, "quiz": quiz}) # might need to send quiz.id instead
question_serializer.is_valid()
question_serializer.save()
return quiz
and update your QuestionSerializer to use AnswerSerializer the same way (or you can create Answers explicitly there)
Suppose I have my Model class as below.
class BankAccount(db.Model):
a = db.Column(db.Integer, primary_key=True)
b = db.Column(db.String(80))
And my Schema looks like the below.
class CreateAccountSchema(ma.SQLAlchemyAutoSchema):
class Meta:
model = BankAccount
load_instance = True
ordered = True
But here I want to define a field c which doesnt exists in my Model class as it should only be used for dump(ing) values and not storing in the database.
Something like...
class CreateAccountSchema(ma.SQLAlchemyAutoSchema):
class Meta:
model = BankAccount
dump_only = ('c',)
load_instance = True
ordered = True
c = #somedefination
You could do something like this:
class CreateAccountSchema(ma.SQLAlchemyAutoSchema):
class Meta:
model = BankAccount
load_instance = True
ordered = True
c = fields.Method("get_data")
def get_data(self, obj):
if hasattr(obj, "data"):
return obj.data
return None
That would dump the additional field.
You could use it like this:
bank_account = db.session.query(BankAccount).first()
bank_account.data = "whatever"
schema = CreateAccountSchema()
schema.dump(bank_account)
More infos here.
I have two models Question and Options
class Question(models.Model):
question_identifier = models.CharField(max_length=255)
question_text = models.TextField(blank=False)
question_category = models.ManyToManyField('Category')
question_tags = models.CharField(max_length=255, blank=True)
class Options(models.Model):
question = models.OneToOneField('Question', related_name='options', blank=False, null=False)
option1 = models.CharField(max_length=255,blank=False,null=True)
option2 = models.CharField(max_length=255,blank=False,null=True)
option3 = models.CharField(max_length=255,blank=True,null=True)
option4 = models.CharField(max_length=255,blank=True,null=True)
I have written a serializer for Question model which serializes options as well (reverse relation). I want to omit the question field from the Options? Is there a way to achieve this?
My Question Serializer:-
class QuestionSerializer(serializers.ModelSerializer):
"""
Serializer for Question object from qna.models
"""
question_category = CategorySerializer(many=True,write_only=True)
class Meta:
model = Question
fields = ('id', 'options', 'question_identifier','question_text','question_tags','question_category')
depth = 1
You can achieve that by creating a separate serializer for an Options model.And use it instead of default field, without depth value.
class OptionsSerializer(serializers.ModelSerializer):
class Meta:
model = Options
fields = ('option1', 'option2', 'option3')
class QuestionSerializer(serializers.ModelSerializer):
question_category = CategorySerializer(many=True,write_only=True)
options = OptionsSerializer()
class Meta:
model = Question
fields = ('id', 'options', 'question_identifier','question_text','question_tags','question_category')