I have been dabbling with Django CBV lately and have a question. Maybe you have better ideas than I.
Assume I have a airline booking CRM application and I intend to perform a display of a customer for various things. Assume I have a list of Models, for a Customer like Booking, Rating, Customer_Service_Calls, Favourited_Route.
Now, given a DetailView implemented by Django's CBV, I have something like this
class CustomerThreeSixtyView(DetailView):
model = 'Customer'
def get_context_data(self, **kwargs):
context = super(CustomerThreeSixtyView, self).get_context_data(**kwargs)
context['bookings'] = Booking.objects.all.filter(customer_id=request.kwargs['pk']
context['ratings'] = Ratings.objects.all.filter(customer_id=request.kwargs['pk']
context['calls'] = Customer_Service_Calls.objects.all.filter(customer_id=request.kwargs['pk'], status'Open')
context['fav_routes'] = Favourited_Route.objects.all.filter(customer_id=request.kwargs['pk'], status'Open')
return context
Something like this. My question is that, are there better ways to do this? This is the most straightforward way but I'm asking for suggestions because there seem to be bound for something.
What you have done already looks good enough. You are getting what you required in the context and then using it in the template to show the information.
Alternatively, you could directly access bookings for a particular customer in the template without specifying it in the context:
{% for booking in object.booking_set.all %} # object is the customer here
# do what you want to do with the booking here
{% endfor %}
It is even better if you use related_name while linking the customer to Booking:
class Booking(models.Model):
customer = models.ForeignKey(Customer, related_name='bookings')
# other fields
Now, you can directly use the defined related_name to access the bookings for a particular customer:
{% for booking in object.bookings.all %}
# do what you want to do with the booking here
{% endfor %}
And, you can use the same approach for other classes such as Rating, Customer_Service_Calls, Favourited_Route etc.
Related
I was wondering if there is a way to make this more optimised.
class AppTopic(models.Model):
topic = models.CharField(max_length=20) # lowercase (cookies)
class UserTopic(models.Model):
topic = models.CharField(max_length=20) # Any case (cOoKiEs)
app_topic = models.ForeignKey(AppTopic) # related to (cookies -> lowercase version of cOoKiEs)
class User(models.Model):
topics = models.ManyToManyField(UserTopic) # AppTopic stored with any case
The goal is to have all AppTopics be lowercase on the lowest level, but I want to allow users to chose what capitalisation they want. In doing so I still want to keep the relation with it's lowercase version. The topic on the lowest level could be cookies, the user might pick cOoKiEs which should still be related to the orignal cookies.
My current solution works, but requires an entirely new table with almost no use. I will continue using this if there isn't really a smarter way to do it.
There's nothing in the Django model API that would allow you to manipulate values from the models themselves. If you don't want to change the value in the database or in the model instance, you can change how it displays on the template level using the
lower filter in Django template language.
<body>
<div>
{% if condition %}
<h1>{{AppTopic|lower}}</h1>
{% else %}
<h1>{{AppTopic|??}}</h1> #AppTopic but camelcase. There's no camelcase filter in Django
{% endif %}
</div>
</body
Views.py
def View(request, condition)
...
return render(request, 'template.html', {condition:'condition'})
I want to change my Foreign Key to Many To Many field to let the user select multiple categories in a dropdown list.
This is what I already have. After I change Foreign Key to Many To Many I'm getting milion errors, I have to get rid of on_delete=models.CASCADE which is a core of my app. What can I do? Which way should I take? Maybe add another model? I'm so confused, especially when I am a Django newbie. Thank you for your help!
MODELS
class Category(models.Model):
name = models.CharField(max_length=50, unique=True)
def __str__(self):
return f'{self.name}'
class Expense(models.Model):
class Meta:
ordering = ('date', '-pk')
category = models.ForeignKey(Category, null=True,blank=True, on_delete=models.CASCADE)
name = models.CharField(max_length=50)
amount = models.DecimalField(max_digits=8,decimal_places=2)
date = models.DateField(default=datetime.date.today,db_index=True)
def __str__(self):
return f'{self.date} {self.name} {self.amount}'
The clue of the application is to let the user create a category e.g "PC". Then add some expenses like "GPU", "CPU" etc... and let the user link it to the "PC" category. And when the user wants to delete certain categories, all the expenses linked to it, gonna be deleted too. And this is the thing I have already did. BUT NOW I want to let the user search the main table of expenses by multiple categories. And here comes my problem, I don't have a clue how to do it and keep the whole application in one piece with all the functionalities.
SCREENSHOTS:
Categories View with just added PC category
Expense Add View
I don't think there is a simple answer to your question, but here are some resources that might help. First, I don't think you should change your models. From the way you described your application, I think a foreign key model with on_delete=CASCADE is good. The basic idea here is that you need to change your list view function so that it performs a query of your database. Also modify your template.html to include a search bar.
https://github.com/csev/dj4e-samples/tree/master/well
https://www.dj4e.com/lessons/dj4e_ads4
Modify Your List View To Allow The Searching
This is an example of a list view that allows you to search for a single term, and returns anything in the database that matches from any field. This isn't what you want to do exactly, but if you can get this working then you can modify the search conditions for your specific application. What is going on in the code below is that instead of return every item in my Ad table in my SQL database, I filter it based on the search. Then, I pass "ad_list" to the template view. Since I already filtered ad_list based on the search, in the template view it will only list the items that match. This is based on the DJ4E course, and you can watch the video there to get an idea of how he implements the search bar better.
from ads.models import Ad
from django.views import View
from django.shortcuts import render, redirect, get_object_or_404
from django.urls import reverse_lazy, reverse
from django.http import HttpResponse
from django.core.files.uploadedfile import InMemoryUploadedFile
from django.contrib.humanize.templatetags.humanize import naturaltime
from ads.utils import dump_queries
from django.db.models import Q
class AdListView(ListView):
# By convention:
template_name = "ads/ad_list.html"
def get(self, request) :
strval = request.GET.get("search", False)
if strval :
# Simple title-only search
# objects = Ad.objects.filter(title__contains=strval).select_related().order_by('-updated_at')[:10]
# Multi-field search
query = Q(title__contains=strval)
query.add(Q(text__contains=strval), Q.OR)
objects = Ad.objects.filter(query).select_related().order_by('-updated_at')[:10]
else :
# try both versions with > 4 posts and watch the queries that happen
objects = Ad.objects.all().order_by('-updated_at')[:10]
# objects = Ad.objects.select_related().all().order_by('-updated_at')[:10]
# Augment the post_list
for obj in objects:
obj.natural_updated = naturaltime(obj.updated_at)
ctx = {'ad_list' : objects, 'search': strval}
retval = render(request, self.template_name, ctx)
dump_queries()
return retval;
Modify Your Template.html to include a search bar
<form>
<input type="text" placeholder="Search.." name="search"
{% if search %} value="{{ search }}" {% endif %}
>
<button type="submit"><i class="fa fa-search"></i></button>
<i class="fa fa-undo"></i>
</form>
PS, I think you can answer your own question better when you figure it out, so help others and post it!
I am working on a django project where I want to display all the orders of a customer.
This is my models.py:
class Order(models.Model):
customer=models.ForeignKey(Customer,on_delete=models.SET_NULL,null=True,blank=True)
date_ordered=models.DateTimeField(auto_now_add=True)
complete=models.BooleanField(default=False,null=True,blank=False)
transaction_id=models.CharField(max_length=100,null=True)
class OrderItem(models.Model):
product=models.ForeignKey(Product,on_delete=models.SET_NULL,null=True)
order=models.ForeignKey(Order,on_delete=models.SET_NULL,null=True)
quantity=models.IntegerField(default=0,null=True,blank=False)
date_added=models.DateTimeField(auto_now_add=True)
And this is my views.py:
def orders(request):
customer=request.user.customer
order=Order.objects.filter(customer=customer, complete=True)
items=order.orderitem.get(order=order)
return render(request,"orders.html",{'order':order,})
When I open this template it gives me the error: query set object has no attribute orderitem. I want it to give me the orders for which complete=True and all the orderitems under that particular order so that I can iterate over them and show them in my template but that is not happening for me.
PLease help. Any help would be appreciated .
Add related_name="order_items" to the order field in OrderItem as follow.
order=models.ForeignKey(Order,on_delete=models.SET_NULL,null=True, related_name="order_items")
Now you can access the order_items of an order like this
order=Order.objects.filter(customer=customer, complete=True).first()
items = order.order_items
You can use this:
items=OrderItem.objects.all()
and in your template you can use a loop and give a if condition seeing your models like:
{% for ord in orders %}
{% for item in items %}
{% if item.order.id == ord.id %}
This is not the most efficient way as it will iterate over all items in your database but it may work for you
I would like to show possible choices from ManyToManyField (which I have in Homes model) in the Owners form. I have Owners <--Many2Many--> Homes with custom class HomesOwners. In Homes it works out of the box, I don't know how to make it work in Owners.
I am using Django 2.2.4 with Bootstrap 4 and Postgresql. I started my project based on django-bookshelf project (also just Django and Bootstrap4). I do not use any render. Comment in django-bookshelf project mentioned How to add bootstrap class to Django CreateView form fields in the template?, so I stick to that if it comed to forms.
I'm pretty new to Python (so Django too) and web technologies in general. I googled dozen of different questions/answers but I couldn't find any nice explanation of what is what and how to use it in real life. Most of them ended up with basic usage.
I did some experimentation on my own, but no success so far...
Here is the code
I have two models - Homes/models.py and Owners/models.py
Homes/models.py:
class Homes(models.Model):
id = models.AutoField(primary_key=True)
# other fields
some_owners = models.ManyToManyField(Owners, through='HomesOwners', through_fields=('id_home', 'id_owner'), related_name='some_owners')
# end of fields, some other code in the class like "class Meta" etc.
class HomesOwners(models.Model):
id = models.AutoField(primary_key=True)
id_home = models.ForeignKey(Homes, models.DO_NOTHING, db_column='id_home')
id_owner = models.ForeignKey('owners.Owners', models.DO_NOTHING, db_column='id_owner')
Owners/models.py do not have anything special, no imports from my Homes/models.py etc.
and my forms:
Homes/forms.py:
class HomesForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(HomesForm, self).__init__(*args, **kwargs)
self.fields['some_field_from_homes_model'].widget.attrs = {'class': 'form-control '}
#
# --> no need self.fields for M2M, Django does the work
#
# but I tried also and have a --> Question 2
# self.fields["some_owners"].widget = forms.widgets.CheckboxSelectMultiple()
# self.fields["some_owners"].queryset = HomesOwners.objects.all()
Without any code as "self.fields" for M2M field, Django is able to generate for me list of owners.
Question 1
I would like to get list of Homes in my OwnersForms.
I do not know what to add. I assume that I cannot add
# Owners/models.py
some_homes = models.ManyToManyField(Homes, through='HomesOwners', through_fields=('id_home', 'id_owner'), related_name='some_homes')
because of circular import, am I right?
How do I get my Homes list using self.fields?
What do I need to add to my code?
Question 2
When I've added
# Homes/forms.py
self.fields["some_owners"].widget = forms.widgets.CheckboxSelectMultiple()
self.fields["some_owners"].queryset = HomesOwners.objects.all()
I got
<!-- html page -->
HomesOwners object (1)
HomesOwners object (2)
<!-- and so on... -->
How can I just list Owners?
How to filter/order them so first they would appear Owners not connected to any Home?
Question 3
class HomesOwners(models.Model):
id = models.AutoField(primary_key=True)
id_home = models.ForeignKey(Homes, models.DO_NOTHING, db_column='id_home')
id_owner = models.ForeignKey('owners.Owners', models.DO_NOTHING, db_column='id_owner')
def __str__(self):
return pass #return something
I can't get my head around this. This class connects Homes and Owners. When I'm thinking of Homes I would like to return Owners and vice versa. So it should return different things depending on what object we are using (home or owner). I think this is connected to my 2nd question about:
HomesOwners object (1)
Also...
In homes.html I'm using my M2M like that:
{% for owner in homes.homesowners_set.all %}
{{ owner.id_owner.id }}
{% endfor %}
I would like to write something similar to my owners.html and list homes. This is connected to my previous question, I would like to have full answer if that's possible.
EDIT
With the answer given to me I was able to add Homes to OwnerUpdate view. I have views like that:
owners/views.py
# List View
class OwnersList(ListView):
model = Owners
# Detail View
class OwnersView(DetailView):
model = Owners
# Create View
class OwnersCreate(CreateView):
model = Owners
form_class = OwnersForm
# Setting returning URL
success_url = reverse_lazy('owners_list')
# Update View
class OwnersUpdate(UpdateView):
model = Owners
form_class = OwnersForm
success_url = reverse_lazy('owners_list')
# Delete View
class OwnersDelete(DeleteView):
model = Owners
success_url = reverse_lazy('owners_list')
What change do I need to make to be able to show in OwnersList Homes they own?
In Homes DetailView I am able to show Owners. I would like to do the same for Homes' DetailView and Homes ListView.
I don't really get it what you asking for,
but if I understand your question correctly,
I assume you want to add Homes list (not HomesOwners list) into your Owners form, right?
you can add extra field in your form like this:
class OwnersForm(ModelForm):
# notice the queryset is 'Homes' not 'HomesOwners'
homes = forms.ModelMultipleChoiceField(queryset=Homes.objects.all(), widget=forms.CheckboxSelectMultiple)
class Meta:
model = Owners
fields = ('homes', 'your_other_fields',)
# then you can access in init function too if you want
def __init__(self, *args, **kwargs):
super(OwnersForm, self).__init__(*args, **kwargs)
self.fields['homes'].required = False
then, since it using CheckboxSelectMultiple widget, you can iterate it in your html template like this:
{% for key, value in your_form.homes.field.choices %} <!-- notice '.field.'-->
{{ key }} = {{ value }}
{% endfor %}
you probably need to create custom save too for your form.
for your question 3, it is not about the form?
If you want to show HomesOwners, you are already doing right.
{% for owner in homes.homesowners_set.all %}
{{ owner.id_owner.id }}
{% endfor %}
but it will work if that homes is only 1 object.
if homes is a queryset, you have to iterate it first
{% for home in homes %}
{% for owner in home.homesowners_set.all %}
{{ owner.id_owner.id }}
{% endfor %}
{% endfor %}
sorry if I misunderstanding your questions,
maybe you can provide your views.py too, so I or others can help you more specific
What I want to do?
I have an app have three models:Series,Section and Episode,every one have a one-many query(by ForeignKey). just like this
series-> many Section,section-> many Episode
Now I will show a section with episodes information in series page, but it make more query.
now code
views.py
series = Series.objects.get(id=series_id)
section = Section.objects.filter(series=series)
list.html
{% for item in sections %}
...
{% for episode in item.episode_set.all %}
...
{% endfor %}
...
{%endfor%}
models.py
class Section(models.Model):
series = models.ForeignKey(Series)
....
class Episode(models.Model):
section = models.ForeignKey(Section)
What I want to get ?
an example code tell me how to query in views.py and use just little query.
you can guess, in my code, if here are many section and many episode, it will have many query.
Some idea.
I use Laravel Before, In Laravel , it has a hasMany Function, I can use it to get other models items(Define by belongsTo).
Is Django has same function?
If in template you need only episodes, you can query just them with single query
Episode.objects.filter(section__series=series_id)
But if you need all data then you can use prefetch_related Django docs.
The simplest example looks enough for your code
series = Series.objects.filter(id=series_id).prefetch_related('section_set', 'section_set__episode_set').get()
After this calls to series.section_set.all() and to section.episode_set.all() will not produce extra query.