Foo.objects.get(pk="foo")
<Foo: test>
In the database, I want to add another object which is a copy of the object above.
Suppose my table has one row. I want to insert the first row object into another row with a different primary key. How can I do that?
Just change the primary key of your object and run save().
obj = Foo.objects.get(pk=<some_existing_pk>)
obj.pk = None
obj.save()
If you want auto-generated key, set the new key to None.
More on UPDATE/INSERT here.
Official docs on copying model instances: https://docs.djangoproject.com/en/2.2/topics/db/queries/#copying-model-instances