On Mon, Mar 2, 2009 at 2:56 PM, limas <limasathyanan...@gmail.com> wrote:
>
> thank you Alex for your valuable reply.
> but i am still not able to find out the solution.
> i tried this:
> dataobj=DataValue.objects.filter(Q(file=file.id)|Q(mnem=1)|Q(mnem=2))
> but it is not working fine. it is returning every thing.
>
> can you suggest some thing more. It will realy help a newbie like me.
> thanks .....
>
> Lima
>
>
>
> On Mar 3, 12:40 am, Alex Gaynor <alex.gay...@gmail.com> wrote:
> > On Mon, Mar 2, 2009 at 2:36 PM, limas <limasathyanan...@gmail.com>
> wrote:
> >
> > > Hello.....
> >
> > > my project deals with mnemonic-data pairs.
> > > so I have model like this:
> >
> > > class DataValue(models.Model):
> > > file=models.ForeignKey(File)
> > > row=models.IntegerField()
> > > mnem=models.IntegerField()
> > > value=models.CharField(max_length=2000)
> >
> > > class Curve(models.Model):
> > > file=models.ForeignKey(File)
> > > mnem=models.CharField(max_length=100)
> >
> > > mnem field of DataValue contains the curve id, but it not set as the
> > > foreign key.
> > > so for each set of mnemonic data pairs for same file id i am trying to
> > > maintain row numbers.
> >
> > > where i am failing is that ......
> > > i want to get a particular two mnemonic pairs.
> > > my query is like this:
> >
> > > dataobj=DataValue.objects.filter(file=file.id).filter(mnem=1,mnem=2)
> > > where 1 and 2 are the curve ids for a particular condition.
> >
> > > but i am getting only records corresponding to mnem=2.
> >
> > > any valuable suggestions ? please help me......
> > > i think it might be some minor misunderstatnding.
> >
> > > thanks in advanse
> > > Lima
> >
> > This is a bit about how Python works, when you do filter(mnem=1, mnem=2)
> > since the filter method takes **kwargs that translates that into a
> > dictionary {'mnem': 1, 'mnem': 2}, but wait, python dics don't have
> > duplicate keys, the last key wins, so it just because {'mnem': 2}. To
> fix
> > this you want to seperate it into 2 filter calls
> > filter(mnem=1).filter(mnem=2). But that still probably doesn't do what
> you
> > want, since you can't have a field which has 2 values at once, therefore
> I'm
> > guessing you want to OR them together,
> http://docs.djangoproject.com/en/dev/topics/db/queries/#complex-looku...
> > probably what you want.
> >
> > 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 aren't being very clear on what you're trying to do, but my inclination
is that you want something like:
DataValue.objects.filter(file=file.id).filter(Q(mnem=1)|Q(mnem=2))
Which asks for all DataValue objects where (file=file.id) AND (mnem=1 OR
mnem=2)
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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