I am new in Django and I have been following tutorials online. I am having problem on how to display the comments.
How do i query for comments in views, so i can display comments for a particular post.
Model:
class Post(models.Model):
poster_profile = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.CASCADE, blank=True,null=True)
image_caption = models.TextField(blank=True, null=True)
class Comments (models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.CASCADE, blank=True,null=True)
commented_image = models.ForeignKey(Post, on_delete=models.CASCADE, null=True, blank=True)
comment_post = models.TextField()
Views.py:
def home_view(request):
comment = Comments.objects.all() #This is getting all comment in all post, how do i query for comment in a particular post.
context{'comment':comment}
return render(...)
Template:
{% for com in comment %}
<p>{{ com.comment_post }}</p>
{% endfor %}
You can do
post = Post.objects.get(id=1)
comment = post.comments_set.all()
Following Relationships "Backward"
If a model has a ForeignKey, instances of the foreign-key model will have access to a Manager that returns all instances of the first model. By default, this Manager is named FOO_set, where FOO is the source model name, lowercased. This Manager returns QuerySets, which can be filtered and manipulated as described in the “Retrieving objects” section above.
Note this behaviour can be overridden.
You can override the FOO_set name by setting the related_name parameter in the ForeignKey definition. For example, if the Entry model was altered to blog = ForeignKey(Blog, on_delete=models.CASCADE, related_name='entries'), the above example code would look like this:
Edit #2:
views.py:
def home_view(request):
posts = Post.objects.all().reverse()[5]
context{ 'posts': posts, }
return render(...)
Now in your templates you can do something like:
{% if posts %}
{% for post in posts %}
{{ post.image_caption }}
{% for comment in post.comments_set.all %}
{{ comment.comment_post }}
{% endfor %}
{% endfor %}
{% endif %}
First of all, take a look at Django queryset documentation, especially select_related for this kind of issues (to reduce number of queries to database). I didn't try but following snippet must work.
class Post(models.Model):
poster_profile = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.CASCADE)
image_caption = models.TextField(blank=True, null=True)
class Comments (models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.CASCADE)
commented_image = models.ForeignKey(Post, related_nam="comments", on_delete=models.CASCADE)
comment_post = models.TextField()
...
def home_view(request):
post = Post.objects.filter(id=request.data.get('post_id')).select_related("comments") # specify the post anyhow ..
comments = post.comments
context{'comment': comments}
return render(...)
def home_view(request):
particular_Post= Post.objects.get(id=1)
comment = Comments.objects.get(Post=particular_Post)
context{'comment':comment}
return render(...)
to understund Query in django i suggest U to start by
python manage.py shell
and Import you're Models
Related
I have two models that look like;
class Body(models.Model):
body_id = models.AutoField(primary_key=True)
is_adult = models.BooleanField(default=False)
body = models.TextField()
add_user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
add_date = models.DateTimeField()
edit_user = models.CharField(max_length=25, blank=True, null=True)
edit_date = models.DateTimeField(blank=True, null=True)
category = models.ForeignKey(Category, models.CASCADE)
class Meta:
managed = True
db_table = 'jdb_body'
class BodyTag(models.Model):
body_tag_id = models.AutoField(primary_key=True)
body = models.ForeignKey('Body', models.CASCADE)
tag = models.ForeignKey('Tag', models.CASCADE, db_column='tag')
class Meta:
managed = True
db_table = 'jdb_body_tag'
def __str__(self):
return self.tag
I have a view that looks like;
def index(request):
latest_body_list = Body.objects.all().order_by('-body_id')
context = {
'latest_body_list': latest_body_list
}
return render(request, 'index.html', context)
That view gives me a list Body records no problem. I am trying to display Body records with their corresponding BodyTag records. What am I doing wrong?
You neeed a ManyToManyField in your class Body
tags = models.ManyToManyField('Tag')
To access
body = Body.objects.get(body_id=1)
tags = body.tags.all()
EDIT
My previous answer was incorrect because I did not see the more complex relationship. The problem is this: You have many BodyTag objects to one Body object, but you also have many BodyTag objects to one Tag object. So as shown in the image, BodyTag's BT4 and BT5 belong to Body's BODY1 and BODY2. That's why #chipchap31 is talking of a ManyToMany relationship.
If this is not the relationship you want, and from your comments I do not think that you want a ManyToMany field, then the BodyTag model should be either changed, or perhaps discarded. Perhaps relate Body to Tag directly using the ForeignKey, and then have a field in the Tag model that distinguishes it with the type of tag it is, so one type would be body, and you can use a choices field to show all the different types of Tags.
Previous answer (Incorrect)
If you mean displaying these in your template, then all you have to do is follow the ForeignKey relationship backwards. This is shown in the documentaion for the views, but it would look pretty much the same in the template. Something like:
{% for body in latest_body_list %}
{{ body }}
{% for tag in body.tag_set.all %}
{{ tag }}
{% endfor %}
{% endfor %}
The -set is what tells django to look backward in the ForeignKey relationship.
A perhaps better way, also shown in the documentation would be to define a related_name in your ForeignKey:
class BodyTag(models.Model):
body_tag_id = models.AutoField(primary_key=True)
body = models.ForeignKey('Body', models.CASCADE, related_name='tags')
tag = models.ForeignKey('Tag', models.CASCADE, db_column='tag')
Then your template could be written a little better:
{% for body in latest_body_list %}
{{ body }}
{% for tag in body.tags.all %}
{{ tag }}
{% endfor %}
{% endfor %}
I have a models:
class Post(models.Model):
post_text = models.CharField(max_length=100, unique=True)
slug = models.SlugField(unique=True)
created_at = models.DateTimeField(auto_now_add=True)
class Comment(models.Model):
author = models.ForeignKey(User, on_delete=models.CASCADE, related_name='author')
post_relation = models.ForeignKey(Question, on_delete=models.CASCADE, related_name='comments')
comment_text = models.TextField()
created_at = models.DateTimeField(auto_now_add=True)
is_active = models.BooleanField(default=True)
In my views I need get comments for posts in get_context_data:
class ResultsView(DetailView, FormMixin):
model = Post
template_name = 'posts.html'
form_class = CommentForm
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context['comm'] = Comment.objects.filter(is_active=True)
return context
But in comm i get all comments in db.
In html:
{% for comment in question.comments.all %}
<div class="media mb-4">
<div class="media-body">
<h5 class="mt-0">{{ comment.author }}</h5>
{{ comment.comment_text }}
</div>
</div>
{% endfor %}
I try {% for comment in comm %}, try {% for comment in comm.all %} and always get all comments in db, not only comments in post.
Also I try fix this string in views: context['comm'] = Comment.objects.filter(is_active=True), but don't have a result.
The answer seems to be very simple, but I've already spent several hours trying and reading.
You can filter with:
class ResultsView(FormMixin, DetailView):
model = Post
template_name = 'posts.html'
form_class = CommentForm
def get_context_data(self, **kwargs):
return super().get_context_data(
**kwargs, comms=self.object.comments.filter(is_active=True)
)
and then render with:
{% for comment in comms %}
# …
{% endfor %}
Note: It is normally better to make use of the settings.AUTH_USER_MODEL [Django-doc] to refer to the user model, than to use the User model [Django-doc] directly. For more information you can see the referencing the User model section of the documentation.
Note: The related_name=… parameter [Django-doc]
is the name of the relation in reverse, so from the User model to the Comment
model in this case. Therefore it (often) makes not much sense to name it the
same as the forward relation. You thus might want to consider renaming the author relation to comments.
I am struggling to reference my ForeignKey from a basic DetailView in Django.
The models.py I am using:
class Posts(models.model):
url = models.URLField()
class Comment(models.model):
post = models.ForeignKey(Posts, related_name='comments', on_delete=models.CASCADE)
content = models.CharField(max_length=500, blank=False)
views.py:
class PostDetailView(DetailView):
model = Posts
context_object_name = 'posts'
I am trying to reference the comments in my posts detail page.
posts_details.html:
{% for comment in posts.comments.all %}
{{comment.content}}
{% endfor %}
I have also tried changing posts.comments.all to posts.comments_set.all and still am getting no results.
I feel like it is something small that I am missing, but I can't figure it out.
The data is there, and it was input correctly with the foreign key reference, but I cannot reference it through the detail view.
Edit with answer:
I was able to get this to work fairly simply by adding this to the comment model:
def get_absolute-url(self):
return reverse('post_detail', kwargs={'pk': self.post.pk})
That allowed me to access the post in the post_detail.html with the following loop:
{% for comment in posts.comments.all %}
{{comment.content}}
{% endfor %}
class Posts(models.model):
url = models.URLField()
def get_all_comments(self):
return Comment.objects.filter(post=self.pk)
Use this method, add the returned queryset to the context.
Your Posts model has no comments field ... so posts.comments.all is always empty. Unfortunately you do not get an error message if you try to access non existing fields in template tag
I am a beginner in Django. I am building a Django app, named PhoneReview. It will store reviews related to the latest mobile phone. It will also display phone brands, along with the associated phone models. I have managed to do some protion of the app. Right now, I am a bit confused with a line of code.
I have a code like this in one of my template files:
{% extends 'gamereview/base.html' %}
{% block title%}
Detail
{% endblock %}
{% block content %}
<h3>This is the review for {{game.title}} </h3>
<ul>{% for review_item in game.review_set.all %}
<li>{{ review_item.review }}</li>
{% endfor %}
</ul>
{% endblock %}
I don't understand this portion:
<ul>{% for review_item in game.review_set.all %}
What does this line mean?
Here are the codes in models.py:
from django.db import models
from django.template.defaultfilters import slugify
# Create your models here.
class Tag(models.Model):
label = models.CharField(max_length=20)
def __str__(self):
return self.label
class Game(models.Model):
title = models.CharField(max_length=100)
developer = models.CharField(max_length=100)
platform = models.CharField(max_length=50, default='null')
label_tag = models.ManyToManyField(Tag)
slug = models.SlugField(max_length=150, default='null')
def __str__(self):
return self.title
def save(self, *args, **kwargs):
self.slug = slugify(self.title)
super().save(*args, **kwargs)
class Review(models.Model):
game = models.ForeignKey(Game, on_delete=models.CASCADE)
review = models.CharField(max_length=1000)
date = models.DateField(auto_now=True)
slug = models.SlugField(max_length=150, default='null')
def __str__(self):
return self.review
def save(self):
super(Review, self).save()
self.slug = '%i-%s' % (
self.id, slugify(self.game.title)
)
super(Review, self).save()
Here are the codes in views.py:
from django.views import generic
from .models import Game
class GameListView(generic.ListView):
template_name = 'gamereview/gamelist.html'
context_object_name = 'all_games'
def get_queryset(self):
return Game.objects.all()
class ReviewView(generic.DetailView):
model = Game
template_name = 'gamereview/review.html'
Here are the codes in urls.py:
from . import views
from django.urls import path
app_name = 'gamereview'
urlpatterns = [
path('gamereview/', views.GameListView.as_view(), name='gamelist'),
path('gamereview/<slug:slug>/', views.ReviewView.as_view(), name='review'),
]
I am a bit confused by this line: <ul>{% for review_item in game.review_set.all %}. Would you please help me to clarify?
Look at the models; there is a Game class. Apparently you receive an instance of that class in your template under the name game.
The Game class is referenced as a foreign key by Review class. This, due to the way Django ORM works, gives Game class a reverse link .review_set; it contains all review objects that refer to the particular game. Hence game.review_set.
That .review_set attribute is not a list but a DB result set. You can filter it, sort it, etc, but in your case you just fetch all the records from it. Hence game.review_set.all.
Please take some time to read an intro to how Django works, a number of things there cannot be derived from mere common sense.
I'd like to add something that was helpful for me when referencing the related database result set:
In your class, you can specify a "related_name" for the foreign key and use it to reference that result set in your template.
For instance,
class Review(models.Model):
game = models.ForeignKey(Game, on_delete=models.CASCADE, related_name="game_reviews")
And, now you reference this in your template (assuming the context name is all_games):
{% for x in all_games %}
{% all_games.title %} </br>
<ul>{% for review_item in game.game_reviews.all %}
<li>{{ review_item.review }}</li>
{% endfor %}
</ul>
{% endfor %}
Of course, you can further simplify the related_name to just "reviews" and shorten your code that much more. And, it's all very logical when you read it.
I'm trying to display specific content/data based on a logged in user. I want to display only their info. This is what I've tried but I can't get it to work.
views.py
class DemoView(TemplateView):
template_name = 'demographics/demographics.html'
def get(self, request):
demos = Demographics.objects.filter(user=request.user)
context = {
'demos': demos,
}
return render(request, self.template_name, context)
models.py
class Demographics(models.Model):
first_name = models.CharField(max_length=50, null=True)
middle_name = models.CharField(max_length=50, null=True)
last_name = models.CharField(max_length=50, null=True)
user = models.ForeignKey(User, null=True)
HTML
{% if demos %}
{% for demographics in demos %}
<p>First Name</p> {{ demographics.first_name }}
{% endfor %}
{% else %}
<h3>you dont have demo yet</h3>
{% endif %}
I feel like I'm close. What am I missing?
I think the issue may be that you are filtering out all answers from your queryset because the content of request.user is not quite a match for a 'user' object. I don't know why they wouldn't match, but in my code I use:
User.objects.get(username = request.user.username)
I think debugging using pdb will help why the get is not rendering the data properly but if you know how django templateview class handles the context data, you have to modify the code a bit. Here I used get_context_data instead of get and hope this time it will work.
class DemoView(TemplateView):
template_name = 'demographics/demographics.html'
def get_context_data(self, **kwargs):
context = super(DemoView, self).get_context_data(**kwargs)
demos = Demographics.objects.filter(user=self.request.user)
context['demos'] = demos
return context
Also you can check if the table Demographics has the data for the selected user.
full Answer:
Views.py
class DemoView(TemplateView):
template_name = 'demographics/demographics.html'
def get(self, request, *args, **kwargs):
demos = Demographics.objects.filter(user=User.objects.get (username=request.user))
context = {
'demos': demos,
}
return render(request, self.template_name, context)
HTML:
{% if demos %}
{% for demographics in demos %}
<p>First Name</p> {{ demographics.first_name }}
{% endfor %}
{% else %}
<h3>you dont have demo yet</h3>
{% endif %}
urls.py
url(r'^test/', views.DemoView.as_view()),
admin.py
admin.site.register(Demographics)
models.py
class Demographics(models.Model):
first_name = models.CharField(max_length=50, null=True)
middle_name = models.CharField(max_length=50, null=True)
last_name = models.CharField(max_length=50, null=True)
user = models.ForeignKey(User, null=True)
Go to django admin, check your objects, and make sure you're logged in to the account that has demographic objects associated with it.
The above setup works for me, if it doesn't work for you, you're most likely logged in as a user which doesn't have any demographic objects associated with it.
Also, don't name your models as plural, it should be Demographic, because it is a representation of one object. When you filter in views, you name the variable demographics (plural), because the query returns more than one object.