How do you Django Query filter through a processed Model column?

Question

I have the following model:

class Artist(models.Model):
    cell_phone = models.CharField(20)
    pr_phone = modelsCharField(20)

In my template, I can search for all artists for whom the entered phone number match their cell phone or PR phone. Assuming there are no restrictions on how the phone numbers have been initially entered, that is phone number can be stored in any of the following formats:

123 456 7890
(123) 456-7890
123-456-7890

The brute force way to do it is:

# variable input_phone has already been stripped of dashes, braces and spaces
all_artists = Artists.objects.all()
artists = []

for artist in all_artists:
    cell_phone = artist.cell_phone
    pr_phone = artist.pr_phone

    if cell_phone.find(input_phone) >= 0 or pr_phone.find(pr_phone) >= 0:
        artists.append(artist)

return artists

I'm using find because I can also search for all artists who live within a specific area code. Is there another way to the above through Django's query filter?

Answer 1

I think the best way to do this would be to use the django Q object (http://docs.djangoproject.com/en/1.1/topics/db/queries/#complex-lookups-with-q-objects)

So I believe this code would work for you:

from django.db.models import Q
Artists.objects.filter(Q(cell_phone=input_phone) | Q(pr_phone=input_phone))

It should return all Artists that have a cell phone or pr phone number that matches input_phone.

Answer 2

This issue is very similar to relative dates handling. Basically, you need to have two fields: one for user's display (123)-456-789 whatever, and one for internal use, stripped and cleaned out to 12345678. Then querying any number is not a problem, __contains should work just right.

Yes - this is doubles amount of data (while for phone number i think it's negligible), but it's totally worth it.