Fix Python – Create Django model or update if exists

Question 1

I want to create a model object, like Person, if person’s id doesn’t not exist, or I will get that person object.

The code to create a new person as following:

class Person(models.Model):
    identifier = models.CharField(max_length = 10)
    name = models.CharField(max_length = 20)
    objects = PersonManager()

class PersonManager(models.Manager):
    def create_person(self, identifier):
        person = self.create(identifier = identifier)
        return person

But I don’t know where to check and get the existing person object.

Question 2

If you’re looking for “update if exists else create” use case, please refer to @Zags excellent answer

Django already has a get_or_create, https://docs.djangoproject.com/en/dev/ref/models/querysets/#get-or-create

For you it could be :

id = 'some identifier'
person, created = Person.objects.get_or_create(identifier=id)

if created:
   # means you have created a new person
else:
   # person just refers to the existing one

Question

Answer