gistfile1.py

class URLSequence(models.Model):                                                
    id = models.ItemName()
    urls = models.NumberField(required=True, default=0)                         
    
    class Meta:
        connection = simpledb.SimpleDB(settings.AWS_KEY, settings.AWS_SECRET)   
        domain = 'shortener_url'                                                
    
    @staticmethod                                                               
    def id():
        id = '%s_sequence' % settings.AWS_KEY                                   
        try:
            seq = URLSequence.objects.get(id)                                   
        except Exception:
            seq = URLSequence()                                                 
            seq.id = id
            seq.urls = 0                                                        
            seq.save()                                                          
        
        seq.urls = int(seq.urls) + 1                                            
        seq.save()
        return int(seq.urls)