Querying performance

[dsfqce cwfe]

Is quering Provider model significantly less efficient using this pattern?

class Provider(models.Model):

    def __new__(cls, url, *args, **kwargs):

        if 'google' in url:

            return object.__new__(Google)

        elif 'bing' in url:

            return object.__new__(Bing)

    url = models.CharField(primary_key=True)

    sth = models.CharField()

class Google(Provider):

def do_sth(self):

self.sth = 'sth'

self.save()

class Bing(Provider):

def do_sth(self):

self.sth = 'sth else'

self.save()

spam_url = 'https://www.google.pl/search?q=spam'

spam = Provider.objects.get_or_create(url=spam_url)

spam.__class__

<class '__main__.Google'>

eggs_url = 'https://search.yahoo.com/search;?p=eggs'

eggs = Provider.objects.get_or_create(url=eggs_url)

spam.__class__

<class '__main__.Yahoo'>