i have tried a lot to get an answer for my problem , someone tell me if its possible please.
i'm working on a restaurant order management system , and apart of the system is a point of sale at the same time(for cashier) , when a customer visit to the restaurant , the cashier be able to fill a receipt,for example (3 pizza with 2 sandwich)
models.py
class Product(models.Model):
name = models.CharField(max_length=50)
price = models.PositiveIntegerField(default=1)
def __str__(self):
return self.name
class Order(models.Model):
id = models.AutoField(primary_key = True)
products = models.ManyToManyField(Product ,through='ProductOrder')
#property
def total(self):
return self.productorder_set.aggregate(
price_sum=Sum(F('quantity') * F('product__price'),
output_field=IntegerField()) )['price_sum']
class ProductOrder(models.Model):
product = models.ForeignKey(Product, on_delete=models.CASCADE ,
null=True,blank=True)
ordering = models.ForeignKey(Order, on_delete=models.CASCADE ,
blank=True)
quantity = models.IntegerField(default=1)
#to make a new instance from order,but doesnt make! before saving
#ProductOrder
def create_order(sender, instance, **kwargs):
instance.ordering.save()
pre_save.connect(create_order,sender=ProductOrder)
forms.py
class ProductOrdering(forms.ModelForm):
class Meta:
model = ProductOrder
fields = ['product','ordering','quantity']
views.py
class ProductOrderCreate(CreateView):
form_class = ProductOrdering
model = ProductOrder
template_name = 'create_product_order.html'
success_url = '/orders/'
def form_valid(self,form):
form.instance.ordering = Order.objects.order_by('-pk')[0]
return super(ProductOrderCreate,self).form_valid(form)
if the signal(pre_save) worked fine and after select a product,creating another field automatically(not formset) it will solve the problem
i asked alot everywhere but still not solved , please someone help me out i much appreciate
i think this is not specific to django problem, this is logical problem, so for me i will create an API endpoint to create "order", so from frontend send payload with identifier where will be store on db, what i mean identifier here is every "order" has 1 unique stuff so even customer order 3 items that item will be identify by their identifier.
Related
I am figuring how can I manage this situation with django-import-export using the same excel and differents models with differents djangoapps. I have the following models:
# employees/models.py
class Employee(models.Model):
name = models.CharField(max_length=100)
job = models.ForeignKey(Job, on_delete=models.SET_NULL, null=True, blank=True)
# jobs/models.py
class Job(models.Model):
value = models.CharField(max_length=100)
department = models.ForeignKey(Department, on_delete=models.SET_NULL, null=True, blank=True)
place = models.ForeignKey(Place, on_delete=models.SET_NULL, null=True, blank=True)
class Department(models.Model):
value = models.CharField(max_length=100)
business = models.ForeignKey(Business, on_delete=models.SET_NULL, null=True, blank=True)
class Place(models.Model):
value = models.CharField(max_length=100)
business = models.ForeignKey(Business, on_delete=models.SET_NULL, null=True, blank=True)
class Business(models.Model):
name = models.CharField(max_length=100)
On excel I have following values:
xls_employee_name, xls_employee_job, xls_business_name
Jon Doe, Web Developer, Company 1
I know how to import employee name and his job because Job is directly related by ForeignKey. But how can I import business name?
Below is the code for employee name and his job:
# employees/resource.py
class EmpleadoResource(resources.ModelResource):
name = fields.Field(attribute='nombre', column_name='Nombre')
job = fields.Field(
column_name='xls_employee_job',
attribute='job',
widget=ForeignKeyWidget(
Job,
field='value'
))
class Meta:
model = Employee
fields = ('name','job',)
skip_unchanged = True
def before_import_row(self, row, **kwargs):
self.job = row["xls_employee_job"]
def after_import_instance(self, instance, new, row_number=None, **kwargs):
Job.objects.get_or_create(name=self.job)
Is it possible to import business name using one excel? I appreciate if someone could guide me. I'm also pretty new with django.
thank you for all your answers. I finally manage it and this is the solution(it was a little trickier for me, but very simple. I tried to translate all spanish names to english, sorry if I misslooked some):
# employees/resource.py
class EmployeeResource(resources.ModelResource):
name = fields.Field(attribute='name', column_name='Name')
job = fields.Field(
column_name='xls_employee_job',
attribute='job',
widget=ForeignKeyWidget(
Job,
field='value'
))
place = fields.Field(attribute='place', column_name='xls_place_column')
department = fields.Field(attribute='department', column_name='xls_department_column')
business = fields.Field(attribute='business', column_name='xls_business_name')
class Meta:
model = Employee
fields = ('name','job','place','department','business')
skip_unchanged = True
def before_import_row(self, row, **kwargs):
self.job = row["xls_employee_job"]
self.place = row["xls_place_column"]
self.department = row["xls_department_column"]
self.business = row["xls_business_name"]
def after_import_instance(self, instance, new, row_number=None, **kwargs):
Job.objects.get_or_create(name=self.job)
Centro.objects.get_or_create(name=self.centro)
Departamento.objects.get_or_create(name=self.departamento)
Empresa.objects.get_or_create(nombre=self.empresa)
I was stucked using widgets for business, department and place, but it was not necessary
Option 1
You can assign the column value for each row to a temporary attribute on the model (it doesn't matter that this attribute is not in the Employee model):
def before_import_row(self, row, **kwargs):
self.job = row["xls_employee_job"]
# assign row value to a temporary attr
self.business = row["xls_business_name"]
def after_import_instance(self, instance, new, row_number=None, **kwargs):
Job.objects.get_or_create(name=self.job)
# create instance using temp attr value
Business.objects.get_or_create(name=self.business)
Option 2
You can create all Business instances by processing the dataset in a batch before processing the Employee resources:
def before_import(self, dataset, using_transactions, dry_run, **kwargs):
for row in dataset.dict:
business = row["xls_business_name"]
Business.objects.create(name=business)
Note that you could use bulk_create() here to make this process more efficient.
Add transaction protection as you see fit, and bear in mind that the Business and Job entities will be created even if your import fails.
I am testing forms and nesting models in django. In my Project a Person can enter departure, arrival (city names) and choose a weekly day (Mon-Fri). Maybe he drives every “Tuesday” from Amsterdam to Paris. I wanted this constellation to be unique – just for fun. So If another user enters the same route the relation should be linked to the same Car.object.
Models.py
class Person(models.Model):
name = models.CharField(max_length=255, blank=False, unique=True)
route = models.ManyToManyField('Car')
def __str__(self):
return self.name
class Car(models.Model):
name = models.CharField(max_length=255, blank=False, unique=True)
weekdays = models.ForeignKey('Week', null=True, blank=False, on_delete=models.SET_NULL)
departure = models.CharField(max_length=255, blank=False)
arrival = models.CharField(max_length=255, blank=False)
class Meta:
unique_together = ['weekdays', 'departure', 'arrival'] # --- Unique combination
def __str__(self):
return self.name
class Week(models.Model):
day = models.CharField(max_length=255, blank=False, unique=True)
def __str__(self):
return self.day
views.py
class RouteCreateView(CreateView):
model = Person
template_name ="testa/create_route.html"
form_class = RouteForm
success_url = reverse_lazy('testa:testa_home')
def form_valid(self, form):
return super().form_valid(form)
forms.py
class RouteForm(forms.ModelForm):
# --- apply ChoiceField
day = forms.ModelChoiceField(queryset=None)
car_name = forms.CharField()
departure = forms.CharField()
arrival = forms.CharField()
class Meta:
model = Person
fields = [
'name'
]
def __init__(self, *args, **kwargs):
super(RouteForm, self).__init__(*args, **kwargs)
self.fields['day'].queryset = Week.objects.all()
def save(self, commit=True):
personData = super().save(commit)
data = self.cleaned_data
carData = Car(name=data['car_name'], weekdays=data['day'], departure=data['departure'], arrival=data['arrival'])
if commit:
carData.save()
personData.route.add(carData) # --- save m2m relation
return personData
If i enter two times for example „“Tuesday” from Amsterdam to Paris “ then an Error Message appears obviously, this error message (it´s german), telling me I have a double entry / Key.
Question
So my save()Method does not work because I need some kind of logic, so that Django takes the existing car.object or creates a new - if it is not a double entry. But I do not know where to start? The easiest way would be to get some kind of response from my model meta option Car.unique_together so "if it´s an “double-key error” then take the existing object". Is there a way to fetch the response? And what kind of Values it would be, only errors, could not find any hint in the doc? Or should I try some logic with exists()
That was my kind of idea / approach of a new save() 😊
def save(self, commit=True):
personData = super().save(commit)
data = self.cleaned_data
carData = Car(name=data['car_name'], weekdays=data['day'], departure=data['departure'], arrival=data['arrival'])
if commit:
# Check if database sends unique_together response
# if yes
if Car.Meta.unique_together is True:
getAlternative = Car.object.get(Meta.unique_together) # --- get the object which already exist
personData.route.add(getAlternative) # --- save m2m relation
# if not
else:
carData.save() # --- save object
personData.route.add(carData) # --- save m2m relation
return personData
obviously i get a error message: type object 'Car' has no attribute
'Meta'
Theres get_or_create for such use case: https://docs.djangoproject.com/en/2.2/ref/models/querysets/#get-or-create
...
car, created = Car.objects.get_or_create(
weekdays=data['day'],
departure=data['departure'],
arrival=data['arrival'],
defaults = dict(name=data['car_name']),
)
personData.route.add(car)
...
Obviously given name gets ignored if another car with same weekdas, departure, arrival has been found.
I suggest to put the code for creating the car and adding the route in a transaction.atomic() https://docs.djangoproject.com/en/2.2/topics/db/transactions/#django.db.transaction.atomic
I wanna summarize the current stock quantity of each item in django admin.
In item page, each item have a column, and I wanna show the number in each column of item.
This is my model:
from django.contrib.auth.models import User
from django.db import models
class Item(models.Model):
item_name = models.CharField(max_length=128)
class In(models.Model):
in_date = models.DateTimeField()
item = models.ForeignKey(Item, on_delete=models.CASCADE, related_name='ins')
quantities = models.IntegerField()
class Out(models.Model):
out_date = models.DateTimeField()
item = models.ForeignKey(Item, on_delete=models.CASCADE, related_name='outs')
quantities = models.IntegerField()
Model In means stock-in, Out means stock-out
I write functions in my admin.py like below:
class ItemAdmin(admin.ModelAdmin):
list_display = ['item_name', 'pattern', 'vendor', 'item_ins', 'item_outs']
def item_ins(self, obj):
return obj.ins.aggregate(Sum('quantities')).get('quantities__sum')
item_ins.short_description = 'stock-in'
def item_outs(self, obj):
return obj.outs.aggregate(Sum('quantities')).get('quantities__sum')
item_outs.short_description = 'stock-out'
I already knew how to aggregate total stock-in/stock-out number of each item, but I don't know how to get current stock quantity(stock-in subtract sotck-out) of each item.
Please help me! Thank you!
The simplest but not so efficient implementation would be
def item_quantity(self, obj):
return self.item_ins(obj)-self.item_outs(obj)
def item_quantity(self, obj):
if not self.item_ins(obj):
return '-'
if self.item_outs(obj):
return self.item_ins(obj) - self.item_outs(obj)
return '-'
Thanks to Mr Dharanidhar Reddy , this is my final code .
Sometimes stock-in or stock-out may be empty , so I added some if statement.
Please I'm stuck trying to get around this issue. Guess there is something I'm not getting after looking at other similar questions.
I have these models:
class Dish(BaseModel):
class Meta:
verbose_name_plural = 'dishes'
name = models.CharField(_('dish'), max_length=100)
dish_type = models.CharField(_("dish type"), max_length=100)
price = models.PositiveIntegerField(_("price"))
def __str__(self):
return f"{self.name} costs {self.price}"
class Order(BaseModel):
dishes = models.ManyToManyField(Dish, through='DishOrder')
customer = models.ForeignKey(Customer, on_delete=models.CASCADE)
discount = models.PositiveIntegerField(_("total discount"), blank=True)
total = models.PositiveIntegerField(_("total"), blank=True)
shipping = models.PositiveIntegerField(_("shipping cost"), blank=True)
grand_total = models.PositiveIntegerField(_("grand total"), blank=True)
country = models.CharField(_('country code'), max_length=2)
def __str__(self):
return f"order from {self.customer} at {self.total}"
def get_absolute_url(self):
return reverse('order-details', kwargs={'pk': self.pk})
class DishOrder(models.Model):
dish = models.ForeignKey(Dish, on_delete=models.CASCADE, related_name='dishes')
order = models.ForeignKey(Order, on_delete=models.CASCADE, related_name='dishes')
quantity = models.PositiveIntegerField(_("quantity"))
discount = models.PositiveIntegerField(_("discount"))
price = models.PositiveIntegerField(_('price'))
And the corresponding serializers like so:
class DishOrderSerializer(serializers.ModelSerializer):
class Meta:
model = DishOrder
fields = (
"quantity",
"discount",
"price"
)
class OrderSerializer(serializers.ModelSerializer):
dishes = DishOrderSerializer(source='dish', many=True)
class Meta:
model = Order
fields = (
"id",
"country",
"customer",
"dishes",
"total",
"discount",
"grand_total",
"voucher"
)
So as can be seen, I have a m2m relationship via a through table. However I can't get the serializer to work. This is the error I keep getting:
Got AttributeError when attempting to get a value for field dishes
on serializer OrderSerializer. The serializer field might be named
incorrectly and not match any attribute or key on the Order
instance. Original exception text was: 'Order' object has no attribute
'dish'.
I have been looking through this for some time trying to figure out what the error is. I will appreciate any help
Since you are using related_name='dishes' in model you should use dishes as source to the manytomany objects:
class OrderSerializer(serializers.ModelSerializer):
dishes = DishOrderSerializer(source='dishes', many=True)
or simple:
class OrderSerializer(serializers.ModelSerializer):
dishes = DishOrderSerializer(many=True)
Since source='dishes' redundant in case you named serializer's field dishes also.
Preliminary note: this is a rather newbie question, though I have not found a sufficient answer on StackOverflow; many similar questions, but not this one. So I am asking a new question.
The problem: I'm having difficulty creating records where one field is a foreign key to an existing record, and I do not know what I'm doing wrong in my code.
In my app there are two models in question, a one-to-many relationship between Company and BalanceSheet:
models:
class Company(models.Model):
cik = models.IntegerField(default=0, unique=True)
symbol = models.CharField(max_length=4, unique=True)
name = models.CharField(max_length=255, unique=True)
def __str__(self):
return self.symbol
class BalanceSheet(models.Model):
company = models.ForeignKey(Company,
null=True,
on_delete=models.CASCADE,
related_name='balance_sheets',)
date = models.DateField()
profit = models.BigIntegerField()
loss = models.BigIntegerField()
class Meta:
unique_together = (('company', 'date'),)
def __str__(self):
return '%s - %s' % (self.company, self.date)
serializers:
class BalanceSheetSerializer(serializers.ModelSerializer):
company = serializers.StringRelatedField()
class Meta:
model = BalanceSheet
fields = ('company','date','profit','loss')
class CompanySerializer(serializers.ModelSerializer):
class Meta:
model = Company
fields = ('cik', 'symbol', 'name')
Views:
class BalanceSheetCreate(generics.CreateAPIView):
model = BalanceSheet
queryset = BalanceSheet.objects.all()
serializer_class = BalanceSheetSerializer
urls include:
url(r'^(?P<symbol>[A-Z]{1,4})/create-balance-sheet/$', views.BalanceSheetCreate.as_view(),
name='create_balance_sheet'),
To this point, I have zero problem reading data. However, when trying to create records, I get errors I don't understand:
curl http://localhost:8000/financials/AAPL/create-balance-sheet/ -X POST -d "company=AAPL&date=1968-04-17&profit=1&loss=1"
IntegrityError at /financials/AAPL/create-balance-sheet/
null value in column "company_id" violates not-null constraint
Dropping the company data from that curl command results in the same error.
How do I get around this error? I thought I was telling the api what company I'm interested in, both explicitly in the url and in the post data.
Using python3.6, django 1.11, and djangorestframework 3.7.7
You get the IntegrityError because your code will try to create a new BalanceSheet without a company. That's because StringRelatedField is read-only (see docs) and therefore it's not parsed when BalanceSheetSerializer is used in write mode.
SlugRelatedField is what you need here:
class BalanceSheetSerializer(serializers.ModelSerializer):
company = serializers.SlugRelatedField(slug_field='symbol')
class Meta:
model = BalanceSheet
fields = ('company','date','profit','loss')
To answer my own question, here's what I wound up with. Thanks again go to dukebody.
models:
class Company(models.Model):
cik = models.IntegerField(default=0)
symbol = models.CharField(max_length=4)
name = models.CharField(max_length=255)
def __str__(self):
return self.symbol
class BalanceSheet(models.Model):
company = models.ForeignKey(Company,
null=True,
on_delete=models.CASCADE,
related_name='balance_sheets',)
date = models.DateField()
profit = models.BigIntegerField()
loss = models.BigIntegerField()
class Meta:
unique_together = (('company', 'date'),)
def __str__(self):
return '%s - %s' % (self.company, self.date)
serializers:
class CompanySerializer(serializers.ModelSerializer):
class Meta:
model = Company
fields = ('cik', 'symbol', 'name')
class BalanceSheetSerializer(serializers.ModelSerializer):
company = CompanySerializer(many=False)
class Meta:
model = BalanceSheet
fields = ('company', 'date', 'profit', 'loss')
def create(self, validated_data):
company_data = validated_data['company']
company, created = Company.objects.get_or_create(**company_data)
validated_data['company'] = company
sheet = BalanceSheet.objects.create(**validated_data)
return sheet
I also had to include the full company data within my curl statement as a nested dict.