Thanks for the replies!
if I leave the class person like this:
class Employee(models.Model):
person = models.OneToOneField(Person)
This is SQL generated:
CREATE TABLE "person_person" (
"id" serial NOT NULL PRIMARY KEY,
"name" varchar(50) NOT NULL,
)
;
CREATE TABLE "employee_employee" (
"person_id" integer NOT NULL UNIQUE,
"address_id" integer NOT NULL PRIMARY KEY,
)
And when I need to get the employee data, I call Person or Employee?
I can call the Employee who is using the person_id?
Thanks!!
On 16 abr, 20:06, Ian Clelland <[email protected]> wrote:
> On Sat, Apr 16, 2011 at 1:35 PM, Guevara <[email protected]> wrote:
> > Hello!
> > I have two class, Person and employee, i need make a composition for
> > this (Prefer composition over inheritance):
>
> > class Person(models.Model):
> > name = models.CharField(max_length=50)
> > date_inclusion = models.DateField()
> > # others fields
>
> > class Employee(models.Model):
> > person = models.OneToOneField(Person, primary_key=True)
> > address = models.OneToOneField(Address, primary_key=True)
>
> > The SQL generate is:
>
> > BEGIN;
> > CREATE TABLE "person_person" (
> > "id" serial NOT NULL PRIMARY KEY,
> > "name" varchar(50) NOT NULL,
> > "date_inclusion" date NOT NULL,
> > )
> > ;
> > CREATE TABLE "employee_employee" (
> > "person_id" integer NOT NULL PRIMARY KEY,
> > "address_id" integer NOT NULL PRIMARY KEY,
> > )
> > ;
>
> > This is correct? Should generate the id of the employee?
>
> I don't think it's correct -- a database table shouldn't have two distinct
> primary keys. It's the "primary_key=True" part of your Employee model fields
> that is doing this, and is also stopping an "id" field from being
> automatically generated.
>
> If you write Employee like this:
>
> class Employee(models.Model):
> person = models.OneToOneField(Person)
> address = models.OneToOneField(Address)
>
> Then it will generate SQL like this:
>
> CREATE TABLE "employee_employee" (
> "id" serial NOT NULL PRIMARY KEY,
> "person_id" integer NOT NULL,
> "address_id" integer NOT NULL
> )
> ;
>
> which is probably closer to what you're expecting.
>
> --
> Regards,
> Ian Clelland
> <[email protected]>
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