I just started out django and python so bear with me. (Just a newbie)
I have 3 models Programme, Module and Lecture.
Programme has a variable 'code' which is a foreign key to module.
Module has in turn also a variable 'code' which is a foreign key to lecture.
In lecture I have implemented a function to get dynamic path for uploading files based on the 'code' of programme, 'code' of module and 'title' of lecture.
Here is a snippet of my models.py
from django.db import models
class Programme(models.Model):
code = models.CharField(blank=True, max_length=20, primary_key=True)
title = models.CharField(blank=True, max_length=120)
synopsis = models.TextField(blank=True)
pub_date = models.DateTimeField(blank=True, auto_now=False, auto_now_add=True)
def get_programme_code(self):
return self.code
def __str__(self):
return self.title
class Module(models.Model):
code = models.CharField(blank=True, max_length=20, primary_key=True)
programme = models.ForeignKey(Programme, on_delete=models.CASCADE)
title = models.CharField(blank=True, max_length=120)
synopsis = models.TextField(blank=True)
pub_date = models.DateTimeField(blank=True, auto_now=False, auto_now_add=True)
def get_module_code(self):
return self.code
def __str__(self):
return self.title
class Lecture(models.Model):
def get_upload_to(self):
return 'uploads/%s/%s/%s/%s' % (Programme().get_programme_code(),Module().get_module_code,self.title,filename)
title = models.SlugField(max_length=100)
module = models.ForeignKey(Module, on_delete=models.CASCADE)
lecture_pdf = models.FileField(upload_to=get_upload_to)
lecture_video = models.FileField(upload_to=get_upload_to)
def __str__(self):
return self.title
I know that there is something wrong with my code by the way of accessing 'code's from programme and modules but I cannot figure it out.
And here is a snippet of my unit testing of the models.
from django.test import TestCase
from module_content.models import Programme, Module, Lecture
from django.utils import timezone
from django.core.urlresolvers import reverse
class ProgrammeTest(TestCase):
def create_programme(self, code="E318", title="Computer Science", synopsis="Englobes all computer related fields"):
return Programme.objects.create(code =code, title=title, synopsis=synopsis, pub_date=timezone.now())
def test_programme_creation(self):
t = self.create_programme()
self.assertTrue(isinstance(t, Programme))
self.assertEqual(t.__str__(), t.title)
def test_get_programme_code(self):
t = self.create_programme()
self.assertEqual(t.get_programme_code(), t.code)
class ModuleTest(TestCase):
def create_module(self, code="CSE2233", title="Computer Networks", synopsis="About data transmission"):
v = ProgrammeTest().create_programme()
return Module.objects.create(code=code, programme=v, title=title, synopsis=synopsis, pub_date=timezone.now())
def test_module_creation(self):
t = self.create_module()
self.assertTrue(isinstance(t, Module))
self.assertEqual(t.__str__(), t.title)
class LectureTest(TestCase):
def create_lecture(self, title="Lecture 1"):
t = ModuleTest().create_module()
return Lecture.objects.create(title=title, module=t)
def test_lecture_creation(self):
s = self.create_lecture()
self.assertTrue(isinstance(s, Lecture))
self.assertEqual(s.__str__(), s.title)
def test_get_upload_to(self):
s = self.create_lecture()
self.assertEqual( s.get_upload_to(), 'uploads/E318/CSE2233/lecture-1')
I put the field of title for lecture to be a slugfield, so does django put it automatically as a slug ?
I tried the slugfield and it just return the title as "Lecture 1" instead of "lecture-1", or maybe I'm missing something.
So how can I access the foreign keys from the models and test it that the dynamic upload path is working properly?
I just needed to access the other models by their foreign keys such as self.module.programme.code - to retrieve the code of the programme.
Related
The field which is specified in my models file is not included in the GraphiQL, I have tried to rename the field, delete it and define it again, even changing the type of field also updating the graphene-django package. None of these I have mentioned didn't work. The name of the field I can't get is named book
models.py
from django.db import models
from django.contrib.auth.models import User
from django.utils import timezone
from books.models import Book
class Borrowing(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
book = models.OneToOneField(Book, null=True, on_delete=models.CASCADE)
date = models.DateTimeField(default=timezone.now)
returned = models.BooleanField(default=False)
date_borrowed = models.CharField(blank=True, null=True, max_length=50)
date_returned = models.CharField(blank=True, null=True, max_length=50)
class Meta:
ordering = ['-date']
def __str__(self):
return f'{self.user.username} borrowed {self.book.title}'
schema.py
import graphene
from .mutations.borrowings import *
from backend.functions import pagination
PAGE_SIZE = 12
class BorrowingMutation(graphene.ObjectType):
borrow_book = BorrowBook.Field()
return_book = ReturnBook.Field()
class BorrowingQuery(graphene.ObjectType):
borrowings = graphene.List(BorrowingType)
users_borrowings = graphene.List(BorrowingType, page=graphene.Int())
def resolve_borrowings(self, info):
return Borrowing.objects.all()
def resolve_users_borrowings(self, info, page):
user = info.context.user
borrowings = Borrowing.objects.filter(user=user, returned=False)
borrowings = pagination(PAGE_SIZE, page, borrowings)
return borrowings
Type
class BorrowingType(DjangoObjectType):
class Meta:
model = Borrowing
I am learning web develpoment by django. I am coding according to the book django2byexample.
I found a problem that the book hasn't include
My VScCode printInstance of 'DateTimeField' has no 'year' member
Could someone tell me what` the problem?Thank you.
Here is the code:
from django.db import models
from django.utils import timezone
from django.contrib.auth.models import User
from django.urls import reverse
class PublishedManager(models.Manager):
def get_queryset(self):
return super(PublishedManager, self).get_queryset().filter(status='published')
class Post(models.Model):
STATUS_CHOICES = (('draft', 'Draft'), ('published', 'Published'))
title = models.CharField(max_length=250)
slug = models.SlugField(max_length=250, unique_for_date='publish')
author = models.ForeignKey(User, on_delete=models.CASCADE, related_name='blog_posts')
body = models.TextField()
publish = models.DateTimeField(default=timezone.now())
created = models.DateTimeField(auto_now_add=True)
updated = models.DateTimeField(auto_now=True)
status = models.CharField(max_length=10, choices=STATUS_CHOICES, default='draft')
objects = models.Manager()
published = PublishedManager()
class Meta:
ordering = ('-publish',)
def __str__(self):
return self.title
def get_absolute_url(self):
return reverse('blog:post_detail',args=[self.publish.year,self.publish.month,self.publish.day,self.slug])
i find the answer.
It is the problem of vscode.
we can set in this following step:
Then in Visual Studio Code goto: User Settings (Ctrl + , or File > Preferences > Settings if available ) Put in the following (please note the curly braces which are required for custom user settings in VSC):
{"python.linting.pylintArgs": [
"--load-plugins=pylint_django"
],}
Reference:Class has no objects member
This is a VSC problem. However, you can suppress the warning for a certain code block
def get_absolute_url(self):
#pylint: disable=E1101
return reverse('blog:post_detail',
args=[
self.publish.year,
self.publish.month,
self.publish.day,
self.slug])
Here you only disable the E1101 error for the get_absolute_url method as in the second line of the code. If you want to re-enable it, you can write #pylint: enable=E1101 at the end of the block which it has been disabled for.
sorry for this question, but I had a problem with making a dictionary app for a local language, so I wouldn't need English dictionary, my problem is synonyms, I can't figure out how to implement it in my models
from django.db import models
from django.utils import timezone
from django.contrib.auth.models import User
from django.core.urlresolvers import reverse
# Create your models here.
class Voca(models.Model):
name = models.CharField(max_length=200, unique=True)
def __str__(self):
return self.name
def get_absolute_url(self):
return reverse("voca:detail", kwargs={"id": self.id, "name": self.name})
class Defination(models.Model):
voca = models.ForeignKey(Voca, related_name='definations')
defination = models.CharField(max_length=500)
example = models.CharField(max_length=500)
etymology = models.CharField(max_length=500)
author = models.ForeignKey(User, default=1)
created = models.DateTimeField(auto_now_add=True)
updated = models.DateTimeField(auto_now=True)
class Meta:
ordering = ('created',)
def __str__(self):
return 'Defination given by {} on {}'.format(self.author, self.voca)
class Synonym(models.Model):
words = models.ManyToManyField(Voca, blank=True, related_name='synonyms')
I would like for users to add words, synonyms, antonyms definitions to the database themselves since it is a slang language, so if I can get any help especially for antonyms and synonyms I would really appreciate... thanks
My suggestion would be to remove the Synonym model and add fields to your Defination model.
class Defination(models.Model):
voca = models.ForeignKey(Voca, related_name='definations')
...
synonyms = models.ManyToManyField(Voca, related_name='synonyms')
antonyms = models.ManyToManyField(Voca, related_name='antonyms')
I am following a tutorial online for Django. The presenter loads in random data as follows:
for i in xrange(100): Vote(link = Link.objects.order_by('?')[0],voter=a).save()
From what I could understand, it goes from 0 to 100 and creates a new vote. The vote object has a link object. I don't understand what the order_by('?') means.
Here is the model.py file:
from django.db import models
from django.contrib.auth.models import User
from django.db.models import Count
class LinkVoteCountManager(models.Manager):
def get_query_set(self):
return super(LinkVoteCountManager, self).get_query_set().annotate(
votes=Count('vote')).order_by("-votes")
class Link(models.Model):
title = models.CharField("Headline", max_length=100)
submitter = models.ForeignKey(User)
submitted_on = models.DateTimeField(auto_now=True)
rank_score = models.FloatField(default=0.0)
url = models.URLField("URL", max_length=250, blank=True)
description = models.TextField(blank=True)
with_votes = LinkVoteCountManager()
objects = models.Manager()
def __unicode__(self):
return self.title
class Vote(models.Model):
voter = models.ForeignKey(User)
link = models.ForeignKey(Link)
def __unicode__(self):
return "%s voted %s" %(self.voter.username, self.link.title)
Is it possible to have a field in a Django model which does not get stored in the database.
For example:
class Book(models.Model):
title = models.CharField(max_length=75)
description models.CharField(max_length=255, blank=True)
pages = models.IntegerField()
none_db_field = ????
I could then do
book = Book.objects.get(pk=1)
book.none_db_field = 'some text...'
print book.none_db_field
Thanks
As long as you do not want the property to persist, I don't see why you can't create a property like you described. I actually do the same thing on certain models to determine which are editable.
class Email(EntryObj):
ts = models.DateTimeField(auto_now_add=True)
body = models.TextField(blank=True)
user = models.ForeignKey(User, blank=True, null=True)
editable = False
...
class Note(EntryObj):
ts = models.DateTimeField(auto_now_add=True)
note = models.TextField(blank=True)
user = models.ForeignKey(User, blank=True, null=True)
editable = True
Creating a property on the model will do this, but you won't be able to query on it.
Example:
from django.db import models
class Person(models.Model):
first_name = models.CharField(max_length=30)
last_name = models.CharField(max_length=30)
def _get_full_name(self):
return "%s %s" % (self.first_name, self.last_name)
def _set_full_name(self, combined_name):
self.first_name, self.last_name = combined_name.split(' ', 1)
full_name = property(_get_full_name)
full_name_2 = property(_get_full_name, _set_full_name)
Usage:
from mysite.models import Person
a = Person(first_name='John', last_name='Lennon')
a.save()
a.full_name
'John Lennon'
# The "full_name" property hasn't provided a "set" method.
a.full_name = 'Paul McCartney'
Traceback (most recent call last):
...
AttributeError: can't set attribute
# But "full_name_2" has, and it can be used to initialise the class.
a2 = Person(full_name_2 = 'Paul McCartney')
a2.save()
a2.first_name
'Paul'
To make it an instance variable (so each instance gets its own copy), you'll want to do this
class Book(models.Model):
title = models.CharField(max_length=75)
#etc
def __init__(self, *args, **kwargs):
super(Foo, self).__init__(*args, **kwargs)
self.editable = False
Each Book will now have an editable that wont be persisted to the database
If you want i18n support:
# Created by BaiJiFeiLong#gmail.com at 2022/5/2
from typing import Optional
from django.db import models
from django.utils.translation import gettext_lazy as _
class Blog(models.Model):
title = models.CharField(max_length=128, unique=True, verbose_name=_("Title"))
content = models.TextField(verbose_name=_("Content"))
_visitors: Optional[int] = None
#property
def visitors(self):
return self._visitors
#visitors.setter
def visitors(self, value):
self._visitors = value
visitors.fget.short_description = _("Visitors")