Correct way to use get_or_create?

Question

I'm trying to use get_or_create for some fields in my forms, but I'm getting a 500 error when I try to do so.

One of the lines looks like this:

customer.source = Source.objects.get_or_create(name="Website")

The error I get for the above code is:

Cannot assign "(<Source: Website>, False)": "Customer.source" 
   must be a "Source" instance.

Answer 1

get_or_create returns a tuple.

customer.source, created = Source.objects.get_or_create(name="Website")

Answer 2

From the documentation http://www.djangoproject.com/documentation/models/get_or_create/:

# get_or_create() a person with similar first names.
>>> p, created = Person.objects.get_or_create(first_name='John', last_name='Lennon', defaults={'birthday': date(1940, 10, 9)})

# get_or_create() didn't have to create an object.
>>> created
False

It looks like you need to be returning into a tuple, instead of a single variable, do like this:

customer.source,created = Source.objects.get_or_create(name="Website")

Answer 3

The issue you are encountering is a documented feature of get_or_create.

When using keyword arguments other than "defaults" the return value of get_or_create is an instance. That's why it is showing you the parens in the return value.

you could use ustomer.source = Source.objects.get_or_create(name="Website")[0] to get the correct value.

Here is a link for the documentation: http://docs.djangoproject.com/en/dev/ref/models/querysets/#get-or-create-kwargs