Create Django model or update if exists

Question

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.

Answer 1

It's unclear whether your question is asking for the get_or_create method (available from at least Django 1.3) or the update_or_create method (new in Django 1.7). It depends on how you want to update the user object.

Sample use is as follows:

# In both cases, the call will get a person object with matching # identifier or create one if none exists; if a person is created, # it will be created with name equal to the value in `name`.  # In this case, if the Person already exists, its existing name is preserved person, created = Person.objects.get_or_create(         identifier=identifier, defaults={"name": name} )  # In this case, if the Person already exists, its name is updated person, created = Person.objects.update_or_create(         identifier=identifier, defaults={"name": name} )