On Mon, Mar 9, 2009 at 9:09 AM, uprising <upris...@gmail.com> wrote:
>
> Thanks for your fast reply..
> You mean unique_together=(node_a, node_b)?
> No, that's not what I meant.
>
> I want to make sure if someone has created
> Edge(node_a=x, node_b=y).save()
> he can't add
> Edge(node_a=y, node_b=x).save()
> because edge is a set of two distinct nodes.
>
> On Mar 9, 8:54 pm, Alex Gaynor <alex.gay...@gmail.com> wrote:
> > On Mon, Mar 9, 2009 at 8:52 AM, uprising <upris...@gmail.com> wrote:
> >
> > > Just reminded of a problem by this post, how can I validate a unique
> > > pair of nodes like this:
> >
> > > class Edge(models.Model):
> > > node_a: models.ForeignKey(Node)
> > > node_b: models.ForeignKey(Node)
> >
> > > I mean if I already have {"node_a": 1, "node_b": 2}, I can't add
> > > {"node_a": 2, "node_b": 1}
> > > How to enforce this restriction efficiently?
> >
> > Are you looking to maintain cross field uniqueness, if so:
> http://docs.djangoproject.com/en/dev/ref/models/options/#unique-together
> >
> > ALex
> >
> > --
> > "I disapprove of what you say, but I will defend to the death your right
> to
> > say it." --Voltaire
> > "The people's good is the highest law."--Cicero
> >
>
You'll need to write some custom validation code to handle that, there's
nothing in DJango(or at the DB level AFAIK) that can enforce that
automatically.
Alex
--
"I disapprove of what you say, but I will defend to the death your right to
say it." --Voltaire
"The people's good is the highest law."--Cicero
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