You could also create a custom model field type - see http://docs.djangoproject.com/en/dev/howto/custom-model-fields/#howto-custom-model-fields
In this case, you could 'inherit' from the built-in IntegerField and override its validation logic.
The more I think about this, I realize how useful this would be for many Django apps. Perhaps a IntegerRangeField type could be submitted as a patch for the Django devs to consider adding to trunk.
This is working for me:
from django.db import models
class IntegerRangeField(models.IntegerField):
def __init__(self, verbose_name=None, name=None, min_value=None, max_value=None, **kwargs):
self.min_value, self.max_value = min_value, max_value
models.IntegerField.__init__(self, verbose_name, name, **kwargs)
def formfield(self, **kwargs):
defaults = {'min_value': self.min_value, 'max_value':self.max_value}
defaults.update(kwargs)
return super(IntegerRangeField, self).formfield(**defaults)
Then in your model class, you would use it like this (field being the module where you put the above code):
size = fields.IntegerRangeField(min_value=1, max_value=50)
OR for a range of negative and positive (like an oscillator range):
size = fields.IntegerRangeField(min_value=-100, max_value=100)
What would be really cool is if it could be called with the range operator like this:
size = fields.IntegerRangeField(range(1:50))
But, that would require a lot more code since since you can specify a 'skip' parameter - range(1:50:2) - Interesting idea though...