Pranshu321/django-recipe

CRUD

Insert

Three methods

Simply Using Constructor

Product(values);

Using objects.create

 Product.objects.create(name="Nexus" , price=10534)

Using Dictornary ** operator

Product.objects.create(**dict_obj)

Update the Data

Product.objects.filter(id=2).update(name="Kia Seltos II") 

OR

car = Product.objects.get(id=2)
car.name = 'Kia Seltos' 

Delete the Instance

Product.objects.filter(id=2).delete()

ORM

• OrderBy: Recipe.objects.all().order_by('-view_count ...: ') For Decending Order

• OrderBy: Recipe.objects.all().order_by('view_count ...: ') For Ascending Order

• vege = Recipe.objects.all().order_by('view_count' ...: )[0:1] (Here [0:1] tells that we limit the response and we want only 1 item)

• Recipe.objects.filter(view_count__gte=55) : Here gte means greater and equal to

Foreign Key Access

queryset = Student.objects.filter(dept__department = "Maths")

• Here the dept is the foreign key and department is the attribute of the model Department. Here is to add the filters dept__department__icontains

query = Student.objects.exclude(dept__department = "Maths")

• It is used to exclude the objects from the queryset.

query.exits() : means it is used to check whether the object exists or not.

query.values(): It will serialize the data or we say it will convert the queryset into json like

query().reverse(): It will reverse the queryset

Agreegate Functions

In [41]: query = Student.objects.aggregate(Avg('student_age'))

In [42]: query
Out[42]: {'student_age__avg': 25.387096774193548}

In [43]: Student.objects.aggregate(Max('student_age'))
Out[43]: {'student_age__max': 30}

In [44]: Student.objects.aggregate(Min('student_age'))
Out[44]: {'student_age__min': 18}

In [45]: Student.objects.aggregate(Sum('student_age'))
Out[45]: {'student_age__sum': 787}