get_or_create update_or_create

django/query.py at master · django/django https://github.com/django/django/blob/master/django/db/models/query.py

def get_or_create(self, defaults=None, **kwargs):
    """
    Look up an object with the given kwargs, creating one if necessary.
    Return a tuple of (object, created), where created is a boolean
    specifying whether an object was created.
    """
    # The get() needs to be targeted at the write database in order
    # to avoid potential transaction consistency problems.
    self._for_write = True
    try:
        return self.get(**kwargs), False
    except self.model.DoesNotExist:
        params = self._extract_model_params(defaults, **kwargs)
        return self._create_object_from_params(kwargs, params)

def update_or_create(self, defaults=None, **kwargs):
    """
    Look up an object with the given kwargs, updating one with defaults
    if it exists, otherwise create a new one.
    Return a tuple (object, created), where created is a boolean
    specifying whether an object was created.
    """
    defaults = defaults or {}
    self._for_write = True
    with transaction.atomic(using=self.db):
        try:
            obj = self.select_for_update().get(**kwargs)
        except self.model.DoesNotExist:
            params = self._extract_model_params(defaults, **kwargs)
            # Lock the row so that a concurrent update is blocked until
            # after update_or_create() has performed its save.
            obj, created = self._create_object_from_params(kwargs, params, lock=True)
            if created:
                return obj, created
        for k, v in resolve_callables(defaults):
            setattr(obj, k, v)
        obj.save(using=self.db)
    return obj, False