On Sunday, July 15, 2012 9:02:39 AM UTC-5, Setiaman wrote:
>
> Hi,
>
> I want to implement hierarchy data model which is quite common in
> Relational Data Model.
>
> Let's say I have Employee model which has the relation to the boss which
> link to the employee model itself.
> It will look like this:
>
> class Employee(models.Model):
> empname = models.CharField(max_length=60)
> boss = models.ForeignKey(Employee)
>
Employee is in the middle of being defined when you make this reference, so
... try something like:
boss = models.ForeignKey('Employee') # delayed evaluation
or:
boss = models.ForeignKey('self') # I think this reads nicer
See https://docs.djangoproject.com/en/dev/ref/models/fields/#foreignkey
> salary = models.integer()
>
>
> Sample Data:
>
> ID empname boss salary
> --------------------------------------------------
> 1 albert null 10000
> 2 bert 1 5000
> 3 Chuck 1 5000
> 4 Donna 3 3000
> 5 Jack 3 2000
>
> Albert is the root with Bert and Chuck under him and Chuck has Donna and
> Jack under him.
>
> I got an error when I tried to sync to the database where Django telling
> me that the employee is not exist in the Foreign key part.
> Is there any way to manipulate this situation?
>
> Cheers,
> Setiaman
>
Regards,
Yarko
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