How do I get the object if it exists, or None if it does not exist?

Question

When I ask the model manager to get an object, it raises DoesNotExist when there is no matching object.

go = Content.objects.get(name=\"baby\")
         


        

Answer 1

This is a copycat from Django's get_object_or_404 except that the method returns None. This is extremely useful when we have to use only() query to retreive certain fields only. This method can accept a model or a queryset.

from django.shortcuts import _get_queryset


def get_object_or_none(klass, *args, **kwargs):
    """
    Use get() to return an object, or return None if object
    does not exist.
    klass may be a Model, Manager, or QuerySet object. All other passed
    arguments and keyword arguments are used in the get() query.
    Like with QuerySet.get(), MultipleObjectsReturned is raised if more than
    one object is found.
    """
    queryset = _get_queryset(klass)
    if not hasattr(queryset, 'get'):
        klass__name = klass.__name__ if isinstance(klass, type) else klass.__class__.__name__
        raise ValueError(
            "First argument to get_object_or_none() must be a Model, Manager, "
            "or QuerySet, not '%s'." % klass__name
        )
    try:
        return queryset.get(*args, **kwargs)
    except queryset.model.DoesNotExist:
        return None