models.py:
class Post(models.Model):
author = models.ForeignKey('User')
text = models.TextField(max_length=320)
created_date = models.DateTimeField(default=timezone.now)
class Likes(models.Model):
post = models.ForeignKey('Post')
liker = models.ForeignKey('User')
created_date = models.DateTimeField(default=timezone.now)
class Meta:
unique_together = ('post', 'liker')
I want to Get newest posts which their likes are more than 70. how can I write that query set with django orm ?
You need to annotate a count of the number of likes then filter on that
Post.objects.annotate(num_likes=Count('likes')).filter(num_likes__gt=70).order_by('-created_date')
You can do QV like this example.
qv = Likes.objects.filter(liker__gt = 70).all()
out = Post.objects.filter(id__in=qv).order_by('-created_at')
Related
I have a Blog Post Model and I have defined a function to calculate the no of likes.
The Model is as follows ->
class Post(models.Model):
user = models.ForeignKey(User, on_delete=models.PROTECT)
title = models.CharField(max_length=255)
description = models.CharField(max_length=1000,null=True)
Tags = models.CharField(max_length = 255,null=True,blank=True)
Created_date = models.DateTimeField(auto_now_add=True)
Updated_date = models.DateTimeField(auto_now=True)
category = models.ForeignKey(Category, on_delete=models.PROTECT)
Likes = models.ManyToManyField(to=User, related_name='Post_likes')
def __str__(self):
return self.title
def likesCount(self):
return self.Likes.count()
Now I am querying the Post Model from the DB to get all the Posts as follows ->
posts = Post.objects.select_related().prefetch_related('images_set','comments_post').annotate(Count('comments_post')).all()
Here when I loop over the posts I can call the likesCount function and it gives me the correct result as well but I want to return the No of likes to the template.
How can I do that?
in your template, try this:
{{ post.likes_set.count }}
and please make the field names lowercase, they are not Classes
I have this two models:
class Posts(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="posts")
creation_date = models.DateTimeField(auto_now_add=True, blank=True)
content = models.TextField(null=True)
class User(AbstractUser):
follows = models.ManyToManyField(settings.AUTH_USER_MODEL, related_name='followed_by')
likes = models.ManyToManyField(Posts, related_name='liked_by')
pass
And I want to add a post to someone`s likes field, so i do:
def change_like(request, post_id):
post = Posts.objects.get(id=post_id)
current_user = User.objects.filter(username=request.user.username).first()
current_user.likes.add(post)
print(post.liked_by)
print(current_user.likes)
But it prints this:
network.User.None
network.Posts.None
Why is this happening? Am I adding the data correctly?
It is adding data into the ManyToMany Field. But you have printed using wrong method.
You can get all the likes of user by current_user.likes.all().
Django Docs: https://docs.djangoproject.com/en/3.1/topics/db/examples/many_to_many/
First of all, please forgive for my newbie questions. I did copy most of the code, and try to understand from Django documents.
Code as below:
models.py
class Order(models.Model):
ORDER_CHOICES = (
('import', 'IMPORT'),
('export', 'EXPORT')
)
storage = models.ForeignKey(Storage, on_delete=models.PROTECT)
order_type = models.CharField(max_length=6, choices=ORDER_CHOICES)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now_add=True)
class Item(models.Model):
def random_barcode():
return str(random.randint(10000000, 99999999))
type = models.ForeignKey(Type, on_delete=models.CASCADE)
order = models.ForeignKey(Order, on_delete=models.CASCADE, null=True)
brand = models.ForeignKey(Brand, on_delete=models.CASCADE)
item_name = models.CharField(max_length=50, help_text='Name of goods, max 50 characters')
barcode = models.CharField(max_length=8, default=random_barcode, unique=True)
production_date = models.DateField()
expired_date = models.DateField()
def __str__(self):
return self.item_type
forms.py
class ItemForm(ModelForm):
class Meta:
model = Item
exclude = ['order',]
fields = ['type', 'brand', 'item_name', 'production_date', 'expired_date']
ItemFormSet = inlineformset_factory(Order, Item, form=ItemForm, extra=1)
views.py
class CreatePO(CreateView):
model = Order
context_object_name = 'orders'
template_name = 'storages/create_po.html'
fields = ['order_type', 'storage',]
*#dun't know how to write below code....*
1st question: how to use inline formset to write the CreatePO view?
2nd question: I need my create PO template as below picture, how to add a "Quantity" field?
This kind of template need Javascript, right? Any alternative solution? I have no knowledge with javascript.
First of all, move the def random_barcode(): before def __str__(self): it looks so ugly formated code.
Then let's have a look in your pic, if you haven't proper experience with Javascript you can use Admin Views from Django, it's much more simple and supported by Django 2.1. Read more if you would like to give permission to everyone in a admin-views page https://docs.djangoproject.com/el/2.1/releases/2.1/#model-view-permission
So quantity will be just added inside Item class
quantity = models.PositiveSmallIntegerField(default=1)
Also for your form, in my opinion, you need modelform_factory, so I suggest to read this one https://docs.djangoproject.com/en/2.1/topics/forms/modelforms/#modelform-factory-function
Let us say I have a model for social network posts, users and likes:
class Post(models.Model):
submitter = models.ForeignKey(User, null=False, default=None)
content = models.CharField()
date = models.DateField()
with_likes = PostLikeCountManager()
objects = models.Manager()
class Like(models.Model):
user = models.ForeignKey(User)
post = models.ForeignKey(Post)
time = models.DateTimeField(auto_now_add=True)
It would be helpful to think of Post model as representing a Facebook post. Now, I would like to limit one like per post per user. How do I achieve that? One way would be to create a composite primary key on (user, post) attributes of Like class. I don't know how to achieve that in Django. The other would be to use unique=True on two attributes simultaneously. Is that possible?
Thanks.
Yes, use unique_together:
class Like(models.Model):
user = models.ForeignKey(User)
post = models.ForeignKey(Post)
time = models.DateTimeField(auto_now_add=True)
class Meta:
unique_together = ('user', 'post')
unique_together will be deprecated in the future version, instead you could apply UniqueConstraint. This and this link gives example code.
class Like(models.Model):
user = models.ForeignKey(User)
post = models.ForeignKey(Post)
time = models.DateTimeField(auto_now_add=True)
class Meta:
constraints = [
models.UniqueConstraint(fields=['user', 'post'], name='unique_user_post'),
]
I have 2 models named 'Author' and 'Entry' as defined below.
class Author(models.Model):
name = models.CharField(max_length=50)
email = models.EmailField()
msgtoauthor = models.TextField()
class Entry(models.Model):
blog = models.ForeignKey(Blog)
headline = models.CharField(max_length=255)
body_text = models.TextField()
pub_date = models.DateTimeField()
authors = models.ManyToManyField(Author)
I am trying to access 'Author.msgtoauthor' from 'Entry'.
I know, I can retrieve the relationship between Entry and Author by
e = Entry.objects.get(authors)
Is it possible to extract the author id?
I know in the backend, Django creates a table for Authors and Entries but I want to update 'msgtoauthors' from a method in 'Entry'.
Thanks In Advance.
Did you mean
for author in my_entry.authors.all():
author.msgtoauth = 'Here is new content'
author.save()
?
Entry.authors returns a RelatedManager and my_entry.authors.all() is a QuerySet, that returns the Author objects. See https://docs.djangoproject.com/en/1.3/ref/models/relations/ and https://docs.djangoproject.com/en/1.3/topics/db/models/#many-to-many-relationships.
(Updated.)
Try this:
class Entry(models.Model):
blog = models.ForeignKey(Blog)
headline = models.CharField(max_length=255)
body_text = models.TextField()
pub_date = models.DateTimeField()
authors = models.ManyToManyField(Author)
def msgtoat(self, message):
self.authors.update(msgtoauthor=message)
For example, to update an entry:
entry.msgtoat('Hello')
If all the authors get the same value you can do:
entry.authors.update(msgtoauthor='Hey there!')
https://github.com/Ry10p/django-Plugis/blob/master/courses/models.py
line 52
class name():
the_thing1 = models.CharField()
another = models.TextField()
class name2():
the_thing2 = models.ForignKey(the_thing1)
another2 = models.ForignKey(another)
-Cheers