how can I filter related (foreign key) objects?

[serek]

Hi

I have not idea how to describe my problem, so I show pice of code:


class Aaa(models.Model):
name = models.CharField(max_length=200, unique=True)
is_active = models.BooleanField()

class Meta:
ordering = ('name',)

def doMagic(self):
date = '2010-05-04'
//here I need to take 10 conencted Bbb objects whcich data is less
then date
previous10days = self.bbb_set.filter(Bbb.date <
date).order_by('data')


class Bbb(models.Model):
date = models.DateField()
value = models.DecimalField(max_digits=7, decimal_places=2)
aaa = models.ForeignKey(Aaa)

a = Aaa()
a.doMagic throw error that Bbb.date is undefined - what can be wrong?

[Matias Aguirre]

Just refer to the field name, you don't need the class:

prev = self.bbb_set.filter(date__lt=date)

Take a look to field lookup rules:
http://docs.djangoproject.com/en/dev/topics/db/queries/#field-lookups-intro

Excerpts from serek's message of Wed Feb 16 20:51:05 -0200 2011:

--
Matías Aguirre <matias...@gmail.com>

[Chris Matthews]

Hi Serek,

 

Try this

    def doMagic(self):

        date = '2010-05-04'

        #//here I need to take 10 conencted Bbb objects whcich data is less then date

        previous10days = Bbb.objects.filter(date__lt=date).order_by('data')

 

Also read up about managers http://docs.djangoproject.com/en/1.2/topics/db/managers/ in case you should consider using it (depending upon how much magic is required from your function).

 

Regards

Chris

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