On 14-8-2012 6:58, Jeff Dickens wrote:
> class Md_model(models.Model):
> Timestamp =
> models.DateTimeField(auto_now_add=True,unique=True,db_index=True)
> def __unicode__(self):
> return self.Timestamp.strftime('%Y %m %d %H:%M')
> def as_dict(self):
> return(model_to_dict(self))
> class Meta:
> abstract = True
>
> class md_10_1(Md_model):
> name='md_10_1'
> dataSource = 'http://192.168.0.10/auto/001'
> n1 = models.DecimalField(max_digits=10,decimal_places=3)
> n2 = models.DecimalField(max_digits=10,decimal_places=3)
> n3 = models.DecimalField(max_digits=10,decimal_places=3)
>
> class md_10_2(Md_model):
> name='md_10_2'
> dataSource = 'http://192.168.0.10/auto/002'
> n4 = models.DecimalField(max_digits=10,decimal_places=3)
> n5 = models.DecimalField(max_digits=10,decimal_places=3)
I'm wondering if this design isn't better:
class DataBatch(models.Model) :
name = models.CharField(max_length=10)
url = models.URLField(max_length=200)
time_stamp = models.DateTimeField(auto_now_add=True, db_index=True)
class DataType(models.Model) :
"""Different data types, n1 through n5 in your example"""
name = models.CharField(max_length=10)
class CollectedData(models.Model) :
batch = models.ForeignKey(DataBatch, related_name='data')
data_type = models.ForeignKey(DataType)
data = models.DecimalField(max_digits=10,decimal_places=3)
> Using a foreign key does't make sense to me since I can't predict that any
> particular model will be in every query.
If you need your own design, then you can actually set a foreign key to
NULL and use hasattr(Md_model, related_name) to test if the foreign key
is available.
--
Melvyn Sopacua
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