33. get_or_create()

This example describes Django version 0.96. For the current example, go here.

get_or_create() does what it says: it tries to look up an object with the given parameters. If an object isn’t found, it creates one with the given parameters.

Model source code

from django.db import models

class Person(models.Model):
    first_name = models.CharField(maxlength=100)
    last_name = models.CharField(maxlength=100)
    birthday = models.DateField()

    def __str__(self):
        return '%s %s' % (self.first_name, self.last_name)

Sample API usage

This sample code assumes the above model has been saved in a file mysite/models.py.

>>> from mysite.models import Person

# Acting as a divine being, create an Person.
>>> from datetime import date
>>> p = Person(first_name='John', last_name='Lennon', birthday=date(1940, 10, 9))
>>> p.save()

# Only one Person is in the database at this point.
>>> Person.objects.count()
1

# 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

# There's still only one Person in the database.
>>> Person.objects.count()
1

# get_or_create() a Person with a different name.
>>> p, created = Person.objects.get_or_create(first_name='George', last_name='Harrison', defaults={'birthday': date(1943, 2, 25)})
>>> created
True
>>> Person.objects.count()
2

# If we execute the exact same statement, it won't create a Person.
>>> p, created = Person.objects.get_or_create(first_name='George', last_name='Harrison', defaults={'birthday': date(1943, 2, 25)})
>>> created
False
>>> Person.objects.count()
2