class Peg(models.Model):
history = OneToManyField(class=PegEntry)
class Hole(models.Model):
peg = models.ForeignKey(class=Peg, blank=True, null=True)
class PegEntry(models.Model):
hole = models.ForeignKey(class=Hole)
start = models.DateTimeField()
end = models.DateTimeField()
I think that's the basic model schema. To find empty holes, you'd write
Hole.objects.filter(peg=None)
To get a list of all pegs that have been in a given hole, use
[peg_entry.peg for peg_entry in
PegEntry.objects.filter(hole=given_hole)]
On Thu, 2006-10-26 at 21:42 -0700, PirahnaBreaks wrote:
> I'm a recovering PHP developer and I'm looking at using Django for my
> next project - I know how to accomplish the following in PHP (well,
> technically it's mostly accomplished in SQL...) but I'd like to know
> how difficult it would be to handle this in Django:
>
> I'm trying to create a model for a certain type of physical object -
> we'll say, a (theoretical) peg. I also have a model for a grid of
> holes. A given peg may occupy any hole, but only one at a time. For
> my particular case, I have a pressing need to know what holes a given
> peg has occupied, and *when*. It would also be nice to be able to pull
> up a list of available holes, or get a complete peg occupancy history
> for a given hole :)
>
> If I was creating a SQL schema by hand, I would create a join table
> with something like these columns:
> peg_id
> hole_id
> occupied_start_time
> occupied_end_time
>
> And then write all the queries by hand. I'd like to know the
> "cleanest" way to work with Django on this - it's a wonderful
> framework, and I'd like the opportunity to learn/switch to Python, but
> if I have to reinvent the wheel, I'm a lot more used to doing that
> writing a PHP app. Does anyone have any ideas or sample code I could
> look at?
>
> Thanks!
>
>
> >
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