Table Master and details with same foreign django - django

Question

I am trying to create two models in django, Reservation and DetailsReservation, i need that models has a same userReservation .Example if i create a Reservation with id: 1 and User: 4, when create a Details with Reservation 1, should copy user in userbyReserva
class Reservation(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
userReservation = models.ForeignKey(User, on_delete=models.CASCADE, default=1)
class DetailsReservation(models.Model):
Reservation = models.ForeignKey(Reservation, blank=False, on_delete=models.CASCADE, null=True)
userbyReserva = #same user that do reservate

Answer 1

You can access the user through the Reservation using a method as property. This is the easiest way to do that.
Some notes about the code:
always use a lower case name for the fields and without the camelNaming.
Avoid plurals on the models' name.
I would avoid using default=1 in a ForeignKey. Better raise an error if the relation is not set. (What happen if the User=1 is deleted?)
Do not copy the data if not necessary, you can use properties to access related field. The user is available only if a reservation is related to the DetailReservation object; detail_reservation.user will return None if the reservation is not set.
I don't understand why you created the reservation relation optional from DetailReservation.
Have a look
class Reservation(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
user = models.ForeignKey(User, on_delete=models.CASCADE, )
class DetailReservation(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
reservation = models.ForeignKey(Reservation, blank=False, related_name='details',
on_delete=models.CASCADE, null=True)
#property
def user(self):
return reservation.user if reservation else return None