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blog objects need to have a primary key value before you can access their tags

i am trying to create a blog by the admin panell. but i am not able to save. Can you please help.
Model.py
class blog(models.Model):
author = models.ForeignKey(User, null=True, on_delete=models.CASCADE)
city_id = models.AutoField(primary_key=True)
blog_title=models.CharField(max_length=200)
created_at = models.DateTimeField(auto_now_add=True)
slug = models.CharField(max_length=500, blank=True)
tags = TaggableManager()
blog_category_name=models.ForeignKey(blog_category,on_delete=models.CASCADE,null=True,blank=True)
blog_sub_category_name=models.ForeignKey(blog_sub_category,on_delete=models.CASCADE,null=True,blank=True)
written_by = models.CharField(max_length=200, default='sandeep')
image_banner= models.ImageField(upload_to='image_banner')
medium_thumbnail = models.ImageField(upload_to='medium_thumbnail')
content = RichTextField() # RichTextField is used for paragraphs
is_authentic=models.BooleanField(default=False)
class Meta: # Plurizing the class name explicitly
verbose_name_plural = 'blog'
def __str__(self): # Dundar Method
return self.blog_title
def save(self, *args, **kwargs): # Saving Modefied Changes
if not self.slug:
self.slug = slugify(self.blog_title)
view.py
def tags(request,tags):
blogs = blog.objects.filter(
Q(blog_title__icontains = tags.replace('-',' ')) |
Q(content__icontains = tags.replace('-',' '))
)
print(tags)
return render(request, 'services/blog-with-sidebar.html',
{'blogs': blogs,'media_url':settings.MEDIA_URL})
For some reason when I'm trying to save the tags and the data I'm getting this error:

Order post by date

I've created a list of post and now I want order this list by date of publishing. If I use order_by(-post_publishing_date) in the view the shell show me this error:
NameError: name 'post_publishing_date' is not defined
models.py
class PostModel(models.Model):
post_title = models.CharField(max_length=70)
post_short_description = models.TextField(max_length=200)
post_contents = models.TextField()
post_publishing_date = models.DateTimeField(auto_now=False, auto_now_add=True)
post_author = models.ForeignKey(AuthorModel, on_delete=models.CASCADE, related_name="connected_author")
post_keyconcept = models.ManyToManyField(KeyConceptModel, related_name="connected_keyconcept")
slug = models.SlugField(verbose_name="Slug", unique="True")
post_highlighted = models.BooleanField(default=False)
def __str__(self):
return self.post_title
def get_absolute_url(self):
return reverse("singlepostManuscriptusView", kwargs={"slug": self.slug})
class Meta:
verbose_name = "Articolo"
verbose_name_plural = "Articoli"
views.py
class SinglePostGDV(DetailView):
model = PostModel
template_name = "manuscriptus_post_detail.html"
class ListPostGDV(ListView):
model = PostModel
template_name = "manuscriptus_home.html"
queryset = PostModel.objects.filter().order_by(-post_publishing_date)
urls.py
urlpatterns = [
path("it/blog/", ListPostGDV.as_view(), name="homeManuscriptusView"),
path("it/blog/<slug:slug>/", SinglePostGDV.as_view(), name="singlepostManuscriptusView"),
]
What I did wrong?

Ad hoc ordering
Well Python is correct. There is no identifier post_publishing_date, you pass the name of the column through a string, so:
class ListPostGDV(ListView):
model = PostModel
template_name = "manuscriptus_home.html"
queryset = PostModel.objects.filter().order_by('-post_publishing_date')
Define an inherent ordering on the model
Note that you can also give a model an "inherent" ordering in the Meta class:
class PostModel(models.Model):
post_title = models.CharField(max_length=70)
post_short_description = models.TextField(max_length=200)
post_contents = models.TextField()
post_publishing_date = models.DateTimeField(auto_now=False, auto_now_add=True)
post_author = models.ForeignKey(AuthorModel, on_delete=models.CASCADE, related_name="connected_author")
post_keyconcept = models.ManyToManyField(KeyConceptModel, related_name="connected_keyconcept")
slug = models.SlugField(verbose_name="Slug", unique="True")
post_highlighted = models.BooleanField(default=False)
def __str__(self):
return self.post_title
def get_absolute_url(self):
return reverse("singlepostManuscriptusView", kwargs={"slug": self.slug})
class Meta:
ordering = ['-post_publishing_date']
verbose_name = "Articolo"
verbose_name_plural = "Articoli"
If you do this, all queries to this model will implicitly be ordered by -post_publishing_date. So this means that you can not "forget" to order the objects properly.
So then you do not have to order it in the views. You can of course only define one such "inherent" ordering, and it is not clear if you want to use one here.

order_by argument should be string:
queryset = PostModel.objects.filter().order_by('-post_publishing_date')

How to display form in django

I'am little confiused because my code in django does't work and I don't know why. I want to create a form displaying in html file. When I click on thh button, the url have to redirect me in the html file where I've put the form code. But the django return me a error
'User' object has no attribute 'nazwa_set'
My models.py is:
from django.db import models
from django.contrib.auth.models import User
class Firma(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE, verbose_name="Użytkownik")
nazwa = models.CharField(max_length=250,verbose_name='Nazwa firmy', unique=False)
class Meta:
verbose_name = 'Firmę'
verbose_name_plural = 'Firmy'
def __str__(self):
return self.nazwa
class Cudzoziemiec(models.Model):
OBYWATELSTWA = (
('RU', 'Rosja'),
('UA', 'Ukraina'),
('BY', 'Białoruś'),
)
TYTUL_POBYTOWY = (
('WZ', 'Wiza'),
('KP', 'Karta pobytu')
)
user = models.ForeignKey(User, on_delete=models.CASCADE, verbose_name="Użytkownik")
nazwa = models.ForeignKey(Firma, on_delete=models.CASCADE, verbose_name="Firma")
obywatelstwo = models.CharField(max_length=250,choices=OBYWATELSTWA, verbose_name="Obywatelstwo")
imie = models.CharField(max_length=80, verbose_name="Imię", unique=False)
nazwisko = models.CharField(max_length=150, verbose_name="Nazwisko", unique=False)
data_ur = models.DateField(auto_now=False, auto_now_add=False, verbose_name="Data urodzenia")
miejsce_ur = models.CharField(max_length=100, verbose_name="Miejsce urodzenia")
paszport = models.CharField(max_length=30, verbose_name="Paszport")
data_start_pasz = models.DateField(auto_now=False, auto_now_add=False, verbose_name="Data wydania paszportu")
data_koniec_pasz = models.DateField(auto_now=False, auto_now_add=False, verbose_name="Data ważności paszportu")
dok_pobytowy = models.CharField(max_length=250,choices=TYTUL_POBYTOWY, verbose_name="Tytuł pobytowy")
data_start_pobyt = models.DateField(auto_now=False, auto_now_add=False, verbose_name="Dokument pobytowy ważny od")
data_koniec_pobyt = models.DateField(auto_now=False, auto_now_add=False, verbose_name="Dokument pobytowy ważny do")
class Meta:
verbose_name = 'Cudzoziemca'
verbose_name_plural = 'Cudzoziemcy'
def __str__(self):
return f'{self.imie} {self.nazwisko}'
in the view.py responsible def for adding the new record:
#login_required
def nowy_pracownik(request):
if request.method == "POST":
nowy_pracownik = CudzoziemiecForm(request.user, request.POST)
if nowy_pracownik.is_valid():
nowy_pracownik.save()
messages.success(request, 'Pomyślnie dodano pracownika !')
return render(request, 'cudzoziemiec/nowy_pracownik_ok.html')
else:
nowy_pracownik = CudzoziemiecForm(request.user)
return render(request, 'cudzoziemiec/nowy_pracownik.html', {'nowy_pracownik':nowy_pracownik})
And on the end here is my forms.py :
class FirmaForm(forms.ModelForm):
class Meta:
model = Firma
fields = ('nazwa',)
class CudzoziemiecForm(forms.ModelForm):
class Meta:
model = Cudzoziemiec
fields = ('nazwa','imie', 'nazwisko','obywatelstwo', 'data_ur','paszport', 'data_start_pasz', 'data_koniec_pasz', 'dok_pobytowy', 'data_start_pobyt', 'data_koniec_pobyt')
def __init__(self, user, *args, **kwargs):
super(CudzoziemiecForm, self).__init__(*args, **kwargs)
self.fields['nazwa'].queryset = user.nazwa_set.all()
self.user = user
def save(self, commit=True):
instance = super(CudzoziemiecForm, self).save(commit=False)
instance.user = self.user
if commit:
instance.save()
return instance
The error is probably somewhere in the forms. py in the class CudzoziemiecForm in line self.fields['nazwa'].queryset = user.nazwa_set.all()

In django default reverse lookup name is modelname_set. So when you trying to get user.nazwa_set.all() this means that there is some model Nazwa related with User. Since in your code you don't have model named Nazwa this line raise the error. I suppose you mean Cudzoziemiec or Firma so to fix problem you need to replace user.nazwa_set.all() with user.firma_set.all() in form's __init__ method.

List posts that fall under a particular catgeory in Django 1.9

I am working on a blog like project but different and I have recently started learning Django. So, in my app we have categories and tags as well. Now there's an Entry model which has ManyToMany relation with both Category and Tag. Now I am trying to get all the Entries which falls under a particular category, it's a similar feature that we have in blogs.
Following is my Tag and Category Model.
class CategoryQuerySet(models.QuerySet):
def category_menu(self):
return self.filter(intopmenu=True)
def top_catgories(self):
return self.order_by("views")[:5]
class Category(models.Model):
name = models.CharField(max_length=50, unique=True)
views = models.IntegerField(default=0)
intopmenu = models.BooleanField(default=False)
created = models.DateTimeField(auto_now_add=True)
modified = models.DateTimeField(auto_now=True)
slug = models.SlugField(unique=True)
objects = CategoryQuerySet.as_manager()
def save(self, *args, **kwargs):
self.slug = slugify(self.name)
super(Category, self).save(*args, **kwargs)
def __str__(self):
return self.name
class Meta:
verbose_name = "Entry Category"
verbose_name_plural = "Entry Categories"
ordering = ["created"]
class Tag(models.Model):
name = models.CharField(max_length=20)
slug = models.SlugField(max_length=200, unique=True)
def __str__(self):
return self.slug
Following is my Entry Model.
class EntryQuerySet(models.QuerySet):
def published(self):
return self.filter(publish=True)
def most_liked(self, num):
return self.order_by("-likes")[:num]
def most_views(self, num):
return self.order_by('-views')[:num]
class Entry(models.Model):
image = models.ImageField(upload_to='entries_images/', null=True)
image_alt = models.CharField(max_length=200, blank=True)
name = models.CharField(max_length=50, blank=True)
text = models.CharField(max_length=500, unique=True)
views = models.IntegerField(default=0)
likes = models.IntegerField(default=0)
publish = models.BooleanField(default=True)
created = models.DateTimeField(auto_now_add=True)
modified = models.DateTimeField(auto_now=True)
source = models.URLField(blank=True)
slug = models.SlugField(unique=True)
categories = models.ManyToManyField(Category)
tags = models.ManyToManyField(Tag)
objects = EntryQuerySet.as_manager()
def save(self, *args, **kwargs):
self.slug = slugify(self.name)
super(Entry, self).save(*args, **kwargs)
def __str__(self):
return self.text
class Meta:
verbose_name = "Entry"
verbose_name_plural = "Entries"
ordering = ["created"]
In my urls.py I have the following url to view all entries by that fall under a particular category.
url(r'^category/(?P<category_slug>[\w\-]+)/$', views.category, name='category'),
Apparently, I don't understand how to write the view to retrieve list of all the entries falling under particular category or tag. Any help will be appreciated. I did refer many blog posts on the web regarding my problem and also searched SO, 1 is a similar question I found but that didn't help much.

try:
def category(request,category_slug):
category = get_object_or_404(Category,slug=category_slug)
return render(request,'template_name.html',{'category':category,'posts':category.entry_set.all()})
More information on https://docs.djangoproject.com/en/1.9/topics/db/examples/many_to_many/

Django: modelchoicefield with multiple modelfields

I would like to request some assistance regarding this matter,
I am fairly new to django and I like it so far.
I have the following model:
class Courses_list(models.Model):
Abbreviation = models.CharField(max_length=100, unique=True)
Course = models.CharField(max_length=100, unique=True)
def save(self, force_insert=False, force_update=False):
self.Abbreviation = self.Abbreviation.upper()
super(Courses_list, self).save(force_insert, force_update)
def __unicode__(self):
return self.Abbreviation
class Job_Posting(models.Model):
Job_Position = models.CharField(max_length=30, null=True, unique=True)
def __unicode__(self):
return self.Job_Position
class Educational_Requirement(models.Model):
fkey = models.ForeignKey('Job_Posting')
Course = models.ForeignKey('Courses_list')
And form:
class CustomField(forms.ModelChoiceField):
def label_from_instance(self, obj):
return obj.Course
class SampleForm(ModelForm):
COURSE = CourseField(queryset=Educational_Requirement.objects.all())
I am saving at:
class MyModel(ModelForm):
course = models.CharField(max_length=50, null = True, blank = True)
In the frontend of my test app SampleForm shows the Course as choices but how do I get the actual value of Course and save it? Because when I view my saved COURSE in the admin it displays Educational_Requirement Object instead of the value I have seen on the dropdown. I can't use __unicode__ at Educational_Requirement as it would raise an error.

I have updated my answer based on your updated question.
Why not use a ManyToManyField and let Django's ORM handle the educational_requirement relationship for you? This way you can use Django's reverse lookup to handle the ForeignKey's name.
class Courses_list(models.Model):
Abbreviation = models.CharField(max_length=100, unique=True)
Course = models.CharField(max_length=100, unique=True)
def save(self, force_insert=False, force_update=False):
self.Abbreviation = self.Abbreviation.upper()
super(Courses_list, self).save(force_insert, force_update)
def __unicode__(self):
return self.Abbreviation
class Meta:
verbose_name = 'Course'
verbose_name_plural = 'Courses'
class Job_Posting(models.Model):
Job_Position = models.CharField(max_length=30, null=True, unique=True)
educational_requirement = models.ManyToManyField(Courses_list)
def __unicode__(self):
return self.Job_Position
class Meta:
verbose_name = 'Job Position'
verbose_name_plural = 'Job Positions'