Given a model:
class Workshop(models.Model):
title = models.CharField(max_length=40)
participants = models.ManyToManyField(User, null=True, blank=True)
(User is django.contrib.auth.models.User)
Users can be in more than one Workshop:
w1.participants = (u1, u2)
w2.participants = (u2, u3)
...
I need to find:1) Number of users participating in 1 workshop (u1, u3)2) Number of users participating in 2 workshop (u2)3) Number of users who don't participating in any workshop (u0)
Could anyone help me please?Thank you very much in advance!
Try this:
from django.db.models import Count
1)
User.objects.annotate(workshop_count=Count('workshop')).filter(workshop_count=1).count()
2)
User.objects.annotate(workshop_count=Count('workshop')).filter(workshop_count=2).count()
3)
User.objects.filter(workshop__isnull=True).count()
More info in the docs
This should do what you want:
workshop_user_dict = {}
user_objects = User.objects.all()
for user in user_objects:
workshops_count = user.workshop_set.all().count()
if not workshops_count in workshop_user_dict:
workshop_user_dict[workshops_count] = []
workshop_user_dict[workshops_count].append(user)
for key, list in workshop_user_dict.items():
print 'There are ' + str(len(list)) + ' users that are participating in ' + str(key) + ' workshops'
Related
class Edge(BaseInfo):
source = models.ForeignKey('Node', on_delete=models.CASCADE,related_name="is_source")
target = models.ForeignKey('Node', on_delete=models.CASCADE,related_name="is_target")
def __str__(self):
return '%s' % (self.label)
class Meta:
unique_together = ('source','target','label','notes')
class Node(BaseInfo):
item_type_list = [('profile','Profile'),
('page','Page'),
('group','Group'),
('post','Post'),
('phone','Phone'),
('website','Website'),
('email','Email'),
('varia','Varia')
]
item_type = models.CharField(max_length=200,choices=item_type_list,blank = True,null=True)
firstname = models.CharField(max_length=200,blank = True, null=True)
lastname = models.CharField(max_length=200,blank = True,null=True)
identified = models.BooleanField(blank=True,null=True,default=False)
username = models.CharField(max_length=200, blank=True, null=True)
uid = models.CharField(max_length=200,blank=True,null=True)
url = models.CharField(max_length=2000,blank=True,null=True)
edges = models.ManyToManyField('self', through='Edge',blank = True)
I have a Model Node (in this case a soc media profile - item_type) that has relations with other nodes (in this case a post). A profile can be the author of a post. An other profile can like or comment that post.
Question : what is the most efficient way to get all the distinct profiles that liked or commented on anothes profile's post + the count of these likes /comments.
print(Edge.objects.filter(Q(label="Liked")|Q(label="Commented"),q).values("source").annotate(c=Count('source')))
Gets me somewhere but i have the values then (id) and i want to pass the objects to my template rather then .get() all the profiles again...
Result :
Thanks in advance
I ended up with iterating over the queryset and adding the objects that i wanted in a dictionary , if the object was already in dictionary , i would count +1 and add the relation in a nested list.
This doesnt feel right but works for now.
posts = Edge.objects.filter(source = self,target__item_type='post',label='Author')
if posts:
q = Q()
for post in posts:
q = q | Q(target=post.target)
contributors = Edge.objects.filter(Q(label="Liked")|Q(label="Commented"),q)
if contributors:
for i in contributors:
if i.source.uid in results:
if i.label in results[i.source.uid]['relation']:
pass
else:
results[i.source.uid]["relation"].append(i.label)
if 'post' in results[i.source.uid]:
results[i.source.uid]['post'].append(i.target)
else:
results[i.source.uid]['post']=[i.target]
else:
results[i.source.uid] = {'profile' : i.source , 'relation':[i.label],'post':[i.target]}
I m trying to override ChoiceField in forms in which i can loop through specific object in my views,
But i Failed cause i only get in the template form only the last item in the list..
need some help to get all the choices i need from this object.
models.py
class TourPackageBuyer(models.Model):
tour = models.ForeignKey(TourPackage, on_delete=models.CASCADE, null =True) production
number_choice = [(i,i) for i in range(6)]
number_choice_2 = [(i,i) for i in range(18)]
number_choice_3 = [(i,i) for i in range(60)]
user = models.CharField(settings.AUTH_USER_MODEL, max_length=200)
num_of_adults = models.PositiveIntegerField(default=0, choices= number_choice_2, null=True)
num_of_children = models.PositiveIntegerField(default=0, choices= number_choice_3, null=True)
hotel = models.ManyToManyField(PackageHotel, blank=True)### thats the field
forms.py
class TourPackageBuyerForm(ModelForm):
class Meta:
model = TourPackageBuyer
date = datetime.date.today().strftime('%Y')
intDate = int(date)
limitDate = intDate + 1
YEARS= [x for x in range(intDate,limitDate)]
# YEARS= [2020,2021]
Months = '1',
# fields = '__all__'
exclude = ('user','tour','invoice','fees', 'paid_case')
widgets = {
'pickup_date': SelectDateWidget(empty_label=("Choose Year", "Choose Month", "Choose Day")),
'hotel': Select(),
# 'pickup_date': forms.DateField.now(),
}
hotel = forms.ChoiceField(choices=[]) ### Thats the field i m trying to override
views.py
def TourPackageBuyerView(request, tour_id):
user = request.user
tour = TourPackage.objects.get(id=tour_id)
tour_title = tour.tour_title
hotels = tour.hotel.all()
form = TourPackageBuyerForm(request.POST or None, request.FILES or None)
### im looping through specific items in the model in many to many field
for h in hotels:
form.fields['hotel'].choices = (h.hotel, h.hotel), ### when this loop it just give the last item in the form in my template!!
You are reassigning the value of choices every time through the loop, so you'll only get the last value you assign once the loop is finished.
You can fix this by replacing this:
for h in hotels:
form.fields['hotel'].choices = (h.hotel, h.hotel),
With this list comprehension:
form.fields['hotel'].choices = [(h.hotel, h.hotel) for h in hotels]
or if you want a tuple as output you can do:
form.fields['hotel'].choices = tuple((h.hotel, h.hotel) for h in hotels)
I have a users table which has 3 types of users Student, Faculty and Club and I have a university table.
What I want is how many users are there in the specific university.
I am getting my desired output but the output is very slow.I have 90k users and the output it is generating it takes minutes to produce results.
My user model:-
from __future__ import unicode_literals
from django.db import models
from django.contrib.auth.models import User
from cms.models.masterUserTypes import MasterUserTypes
from cms.models.universities import Universities
from cms.models.departments import MasterDepartments
# WE ARE AT MODELS/APPUSERS
requestChoice = (
('male', 'male'),
('female', 'female'),
)
class Users(models.Model):
id = models.IntegerField(db_column="id", max_length=11, help_text="")
userTypeId = models.ForeignKey(MasterUserTypes, db_column="userTypeId")
universityId = models.ForeignKey(Universities, db_column="universityId")
departmentId = models.ForeignKey(MasterDepartments , db_column="departmentId",help_text="")
name = models.CharField(db_column="name",max_length=255,help_text="")
username = models.CharField(db_column="username",unique=True, max_length=255,help_text="")
email = models.CharField(db_column="email",unique=True, max_length=255,help_text="")
password = models.CharField(db_column="password",max_length=255,help_text="")
bio = models.TextField(db_column="bio",max_length=500,help_text="")
gender = models.CharField(db_column="gender",max_length=6, choices=requestChoice,help_text="")
mobileNo = models.CharField(db_column='mobileNo', max_length=16,help_text="")
dob = models.DateField(db_column="dob",help_text="")
major = models.CharField(db_column="major",max_length=255,help_text="")
graduationYear = models.IntegerField(db_column='graduationYear',max_length=11,help_text="")
canAddNews = models.BooleanField(db_column='canAddNews',default=False,help_text="")
receivePrivateMsgNotification = models.BooleanField(db_column='receivePrivateMsgNotification',default=True ,help_text="")
receivePrivateMsg = models.BooleanField(db_column='receivePrivateMsg',default=True ,help_text="")
receiveCommentNotification = models.BooleanField(db_column='receiveCommentNotification',default=True ,help_text="")
receiveLikeNotification = models.BooleanField(db_column='receiveLikeNotification',default=True ,help_text="")
receiveFavoriteFollowNotification = models.BooleanField(db_column='receiveFavoriteFollowNotification',default=True ,help_text="")
receiveNewPostNotification = models.BooleanField(db_column='receiveNewPostNotification',default=True ,help_text="")
allowInPopularList = models.BooleanField(db_column='allowInPopularList',default=True ,help_text="")
xmppResponse = models.TextField(db_column='xmppResponse',help_text="")
xmppDatetime = models.DateTimeField(db_column='xmppDatetime', help_text="")
status = models.BooleanField(db_column="status", default=False, help_text="")
deactivatedByAdmin = models.BooleanField(db_column="deactivatedByAdmin", default=False, help_text="")
createdAt = models.DateTimeField(db_column='createdAt', auto_now=True, help_text="")
modifiedAt = models.DateTimeField(db_column='modifiedAt', auto_now=True, help_text="")
updatedBy = models.ForeignKey(User,db_column="updatedBy",help_text="Logged in user updated by ......")
lastPasswordReset = models.DateTimeField(db_column='lastPasswordReset',help_text="")
authorities = models.CharField(db_column="departmentId",max_length=255,help_text="")
class Meta:
managed = False
db_table = 'users'
the query i am using which is producing the desired output but too sloq is:-
universities = Universities.objects.using('cms').all()
for item in universities:
studentcount = Users.objects.using('cms').filter(universityId=item.id,userTypeId=2).count()
facultyCount = Users.objects.using('cms').filter(universityId=item.id,userTypeId=1).count()
clubCount = Users.objects.using('cms').filter(universityId=item.id,userTypeId=3).count()
totalcount = Users.objects.using('cms').filter(universityId=item.id).count()
print studentcount,facultyCount,clubCount,totalcount
print item.name
You should use annotate to get the counts for each university and conditional expressions to get the counts based on conditions (docs)
Universities.objects.using('cms').annotate(
studentcount=Sum(Case(When(users_set__userTypeId=2, then=1), output_field=IntegerField())),
facultyCount =Sum(Case(When(users_set__userTypeId=1, then=1), output_field=IntegerField())),
clubCount=Sum(Case(When(users_set__userTypeId=3, then=1), output_field=IntegerField())),
totalcount=Count('users_set'),
)
First, an obvious optimization. In the loop, you're doing essentially the same query four times: thrice filtering for different userTypeId, and once without one. You can do this in a single COUNT(*) ... GROUP BY userTypeId query.
...
# Here, we're building a dict {userTypeId: count}
# by counting PKs over each userTypeId
qs = Users.objects.using('cms').filter(universityId=item.id)
counts = {
x["userTypeId"]: x["cnt"]
for x in qs.values('userTypeId').annotate(cnt=Count('pk'))
}
student_count = counts.get(2, 0)
faculty_count = counts.get(1, 0)
club_count = count.get(3, 0)
total_count = sum(count.values()) # Assuming there may be other userTypeIds
...
However, you're still doing 1+n queries, where n is number of universities you have in the database. This is fine if the number is low, but if it's high you need further aggregation, joining Universities and Users. A first draft I came with is something like this:
# Assuming University.name is unique, otherwise you'll need to use IDs
# to distinguish between different projects, instead of names.
qs = Users.objects.using('cms').values('userTypeId', 'university__name')\
.annotate(cnt=Count('pk').order_by('university__name')
for name, group in itertools.groupby(qs, lambda x: x["university__name"]):
print("University: %s" % name)
cnts = {g["userTypeId"]: g["cnt"] for g in group}
faculty, student, club = cnts.get(1, 0), cnts.get(2, 0), cnts.get(3, 0)
# NOTE: I'm assuming there are only few (if any) userTypeId values
# other than {1,2,3}.
total = sum(cnts.values())
print(" Student: %d, faculty: %d, club: %d, total: %d" % (
student, faculty, club, total))
I might've made a typo there, but hope it's correct. In terms of SQL, it should emit a query like
SELECT uni.name, usr.userTypeId, COUNT(usr.id)
FROM some_app_universities AS uni
LEFT JOUN some_app_users AS usr ON us.universityId = uni.id
GROUP BY uni.name, usr.userTypeId
ORDER BY uni.name
Consider reading documentation on aggregations and annotations. And be sure to check out raw SQL that Django ORM emits (e.g. use Django Debug Toolbar) and analyze how well it works on your database. For example, use EXPLAIN SELECT if you're using PostgreSQL. Depending on your dataset, you may benefit from some indexes there (e.g. on userTypeId column).
Oh, and on a side note... it's off-topic, but in Python it's a custom to have variables and attributes use lowercase_with_underscores. In Django, model class names are usually singular, e.g. User and University.
I want to auto increament the invoice number which is 3 digits char and 4 digits number.
class Invoice:
invoice_no = models.CharField(max_length=500, null=True, blank=True, validators=[RegexValidator(regex='^[a-zA-Z0-9]*$',message='Invoice must be Alphanumeric',code='invalid_invoice number'),])
I register this model in backend. But now when i click on create invoice in admin the invoice should be auto filled. When i again click on create new invoice in admin, the invoice_number should be incremented by one and should be auto field.
Ex for Invoice number MAG0001, MAG0002, MAG0003 etc and this should be auto field in admin when i click on create new invoice.
Define a function to generate invoice number.
def increment_invoice_number():
last_invoice = Invoice.objects.all().order_by('id').last()
if not last_invoice:
return 'MAG0001'
invoice_no = last_invoice.invoice_no
invoice_int = int(invoice_no.split('MAG')[-1])
new_invoice_int = invoice_int + 1
new_invoice_no = 'MAG' + str(new_invoice_int)
return new_invoice_no
Now use this function as default value in your model filed.
invoice_no = models.CharField(max_length=500, default=increment_invoice_number, null=True, blank=True)
This is just an idea. Modify the function to match your preferred invoice number format.
In above arulmr answer just edit char field
def increment_invoice_number():
last_invoice = Invoice.objects.all().order_by('id').last()
if not last_invoice:
return 'MAG0001'
invoice_no = last_invoice.invoice_no
invoice_int = int(invoice_no.split('MAG')[-1])
width = 4
new_invoice_int = invoice_int + 1
formatted = (width - len(str(new_invoice_int))) * "0" + str(new_invoice_int)
new_invoice_no = 'MAG' + str(formatted)
return new_invoice_no
class Invoice(models.Model):
invoice_no = models.CharField(max_length = 500, default = increment_invoice_number, null = True, blank = True)
This will work fine.
def invoiceIncrement():
get_last_invoice_number
incremente_last_invoice_number
return next_invoice_number
class Invoice:
invoice_no = models.CharField(max_length=500, null=True, blank=True,
validators=[RegexValidator(regex='^[a-zA-Z0-9]*$',
message='Invoice must be Alphanumeric',code='invalid_invoice number'),],
default=invoiceIncrement)
Try this: there are some obvious issues:
if more than one person adds an invoice at the same time, could have collision
will need to make an extra db call each time you create a new invoice.
Also: you may want to just consider using either an auto_increment or UUID.
Maybe this code can help
def increment_invoice_number():
last_invoice = Invoice.objects.all().order_by('id').last()
if not last_invoice:
return 'MAG0001'
invoice_no = last_invoice.invoice_no
new_invoice_no = str(int(invoice_no[4:]) + 1)
new_invoice_no = invoice_no[0:-(len(new_invoice_no))] + new_invoice_no
return new_invoice_no
def invoice_number_gen():
last_invoice = Invoice.objects.all().order_by('id').last()
last_invoice_number = last_invoice.invoice_no
#invoice number format is 'customer_name_short + number' eg: CS003
last_invoice_digits =int(last_invoice_number[2:])
#comment: slicing CS003 to get the number 003 and converting to int.
last_invoice_initials = last_invoice_number[:2]
new_invoice_digits = last_invoice_digits + 1
new_invoice_number = last_invoice_initials + str(new_invoice_digits)
return (new_invoice_number)
Consider the following Django model
Customer(models.Model)
name = models.CharField()
Product(models.Model)
name = models.CharField()
Score(models.Model)
points = models.IntegerField()
customer = models.ForeignKey(Customer)
product = models.ForeignKey(Product)
I would like to get a list of all products annotated with:
total score from all customers
score from the current customer only
I was able to get it working for the total score like this:
products = Product.objects.annotate(total_points = Sum('score__points')).all()
but I don't know how to add an annotation with only the current customer score (if the customer has reviewed the product, None otherwise). I want something like this:
cus = Cusomter.objects.get(pk=123)
products = Product.objects.annotate(total_points = Sum('score__points'),\
current_customer_points= (Score.points where customer=cus and product = this).all()
ids = SortedDict()
for p in Product.objects.annotate(total=Sum('score__points')):
ids[p.pk] = p
for score in Score.objects.filter(customer_id=1, product__in=ids.keys()):
ids[score.product_id].customer_score = score
for p in ids.values():
print p.total, '/', p.customer_score.points if hasattr(p, 'customer_score') else '-'