Django: Validation error in Admin

Question

NEWBIE ALERT!

background:

For the first time, I am writing a model that needs to be validated. I cannot have two Items that have ov

Answer 1

For Django 1.2 see http://docs.djangoproject.com/en/dev/ref/forms/validation/#using-validation-in-practice.

In versions prior to 1.2 you would have to make your own model form for your admin and put your validation methods there! http://docs.djangoproject.com/en/dev/ref/forms/validation/#cleaning-a-specific-field-attribute

from django import forms
from models import Item

class ItemForm(forms.ModelForm):

   class Meta:
       model = Item

   def clean(self, value):
       data = self.cleaned_data
       start = data['startDate']
       end =  data['endDate']
       try:
           item = Item.objects.get(Q(startDate__range=(start,end))|\
                                   Q(endDate__range=(start,end))|\
                                   Q(startDate__lt=start,endDate__gt=end))
           raise forms.ValidationError('.....')
       except:
           pass

   return data 

Then put in your admin form=ItemForm and make sure to define the form somewhere before! For a more detailled description see http://www.jroller.com/RickHigh/entry/django_admin_validation_of_multiple.
Further to assort to django conventions you should name your fields eg. end_date and not endDate. Guess you will not even need to specify their verbose_name then anymore!