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Playing with Django Model Objects - CheatSheet
One must know how to play with Django models in their views in order to create efficient and short functions.
Let's take a model for example.
class Teacher(models.Model):
name = models.CharField(max_length=100)
class Student(models.Model):
name = models.CharField(max_length=100)
roll = models.CharField(max_length=100)
mentor = models.ForeignKey(Teacher, on_delete=models.CASCADE)
reg_date = models.DateTimeField(auto_add_now=True)Let's extract all the students.
students = Student.objects.all()ID is the primary key in every model.
from django.shortcuts import get_object_or_404
def my_view(request):
obj = get_object_or_404(MyModel, pk=1)Or there is another way to do this.
stud = Student.objects.get(pk=1)The last one returns a error in case a student doesn't exist with the following id.
Simple filtering can be done with equating like
studs = Student.objects.filter(name='Ram Kapoor')This will return the list of students whose name is Ram Kapoor.
We can also refer to the details of an attribute with the symbol
We can also refer to the details of an attribute with the symbol
__.stud_2006 = Student.objects.filter(reg_date__year=2006)This will return all the students registered in 2006.
stud_p = Student.objects.filter(name__startswith='P')This will return all the students whose names start with 'P'.
This is used to add many filters in a single filter using | (or), & (and).
stud = Student.objects.filter(Q(name__startswith='P') | Q(reg_date__year=2006))This will return both the students whose names start with 'P' or who are registered in year 2006.
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