#16356: Relationships in Django does not allow CASCADE delete
-------------------------------------+-------------------------------------
Reporter: eguevara2012@… | Owner: nobody
Type: Bug | Status: closed
Component: Database layer | Version: 1.3
(models, ORM) |
Severity: Normal | Resolution: invalid
Keywords: relationship | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by Tim Graham:
Old description:
> Hello!
> I've been through this ticket alert that Django relationships are wrong.
> A simple example:
> An owner has an address.
> A house has an address.
>
> The classes would be:
>
> class Owner(models.Model):
> address = models.ForeignKey(Address)
> #or better
> # address = models.OneToOneField(Address)
>
> class House(models.Model):
> address = models.ForeignKey(Address)
> #or better
> # address = models.OneToOneField(Address)
>
> class Address(models.Model):
> street = models.CharField(max_length=100)
> number = models.IntegerField(default=0)
>
> This is the correct mapping following the logic of object-orientation,
> but this mapping does not allow remove related objects by CASCADE.
> According to the Django doc, the mapping is inverse:
>
> class Owner(models.Model):
> #other fields
>
> class House(models.Model):
> #other fields
>
> class Adress(models.Model):
> street = models.CharField(max_length=100)
> number = models.IntegerField(default=0)
> owner = models.ForeignKey(Owner)
> house = models.ForeignKey(House)
>
> The big problem is that this mapping in the form of owner the address
> form is shown with a select of houses, and in the form of owner is shown
> a form address with a select of owners.
> Look, I want to register an owner and his address, this is end of the
> registration.
> After i want register a house, register your address and there can select
> the owner to associate home with owner.
>
> I urge to carefully read the Hibernate reference manual to understand how
> relationships should be made in Django:
>
> http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html/entity.html
> #entity-mapping-association
>
> I would like to examine this problem because i can not remove an owner
> and remove the house and address by CASCADE, and remove a house and its
> address by CASCADE using my firts example for mapping class.
>
> Regards.
New description:
Hello!
I've been through this ticket alert that Django relationships are wrong.
A simple example:
An owner has an address.
A house has an address.
The classes would be:
{{{
class Owner(models.Model):
address = models.ForeignKey(Address)
#or better
# address = models.OneToOneField(Address)
class House(models.Model):
address = models.ForeignKey(Address)
#or better
# address = models.OneToOneField(Address)
class Address(models.Model):
street = models.CharField(max_length=100)
number = models.IntegerField(default=0)
}}}
This is the correct mapping following the logic of object-orientation, but
this mapping does not allow remove related objects by CASCADE.
According to the Django doc, the mapping is inverse:
{{{
class Owner(models.Model):
#other fields
class House(models.Model):
#other fields
class Adress(models.Model):
street = models.CharField(max_length=100)
number = models.IntegerField(default=0)
owner = models.ForeignKey(Owner)
house = models.ForeignKey(House)
}}}
The big problem is that this mapping in the form of owner the address form
is shown with a select of houses, and in the form of owner is shown a form
address with a select of owners.
Look, I want to register an owner and his address, this is end of the
registration.
After i want register a house, register your address and there can select
the owner to associate home with owner.
I urge to carefully read the Hibernate reference manual to understand how
relationships should be made in Django:
http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html/entity.html
#entity-mapping-association
I would like to examine this problem because i can not remove an owner and
remove the house and address by CASCADE, and remove a house and its
address by CASCADE using my firts example for mapping class.
Regards.
--
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Ticket URL: <https://code.djangoproject.com/ticket/16356#comment:2>
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