how to populate user specific data in django

Question

I have 2 models employee and leave, where Employee is the foreign key in Leave. I want to display the leave requests by a specific employee on a page when they log in. i'm not able to get the leave data populated on, and if there are more than 2 leaves applied by a single employee i get an error saying 2 items found

here is my code

models.py

class Employee(models.Model):
    user=models.OneToOneField(User, on_delete=models.CASCADE)
    no_of_leaves=models.IntegerField(
        null=False,
        validators=[
            MinValueValidator(1),
            MaxValueValidator(24)
        ],
        default=24
    )

   def __str__(self):
        return self.user.username

class Leave(models.Model):
    employee=models.ForeignKey(Employee,on_delete=models.CASCADE,default="")
    start_date=models.DateField(auto_now_add=False)
    end_date=models.DateField(auto_now_add=False)
    req_date=models.DateTimeField(default=datetime.datetime.now())
    STATUS_OPTIONS = (
        ("Approve","Approve"),
        ("Pending","Pending"),
        ("Decline","Decline"),
   )
    approved=models.CharField(max_length=10,choices=STATUS_OPTIONS,default='Pending')

    def __str__(self):
        return self.employee.user.username

    @property
    def date_diff(self):
        return (self.start_date - self.end_date).days

views.py

def home(request):
    user = request.user
    u = User.objects.get(username=user)
    e = Employee.objects.get(user=user.id)
    leave = Leave.objects.get_or_create(employee=e)
    print(leave)

    nofleaves=None
    if user.is_superuser:
        pass
    else:
        nofleaves=u.employee.no_of_leaves
    context={'nofleaves':nofleaves,'leave':leave,}

    return render(request,"leaveApp/home.html",context)

And your problem is? – Branko Radojevic Sep 06 '20 at 18:30 — Branko Radojevic, Sep 06 '20 at 18:30

score 3 · Accepted Answer · answered Sep 07 '20 at 08:47

Just like @Jao said get is to fetch only one data while there is a many to one relationship between Leave and Employee that means there can be multiple Leave for one employee thus get will throw an error.

You should use filter:

Change this line

leave = Leave.objects.get_or_create(employee=e) to something like

leave = Leave.objects.filter(employee=e.id)

if not leave.exists():
    leave = Leave.objects.create(employee=e)

score 2 · Answer 2 · answered Sep 07 '20 at 08:32

This other question might help.

The thing is you should use get for only one data. You shouldn't use get on a many-to-one relathionship. The logic is, there can be multiple Leave by Employee so you can't have a consistent use of get.

What you can use is filter but I'd use related names/related fields which will allow you to use employee.leaves if you define it correctly.

how to populate user specific data in django

2 Answers2