复制/克隆一条查询结果，插入到数据库中

将 pk 值设为 None 即可：

blog = Blog(name='My blog', tagline='Blogging is easy')
blog.save() # blog.pk == 1

blog.pk = None
blog.save() # blog.pk == 2

如果涉及到继承的话，必须将 pk 和 id 的值都设为 None:

class ThemeBlog(Blog):
    theme = models.CharField(max_length=200)

django_blog = ThemeBlog(name='Django', tagline='Django is easy', theme='python')
django_blog.save() # django_blog.pk == 3

django_blog.pk = None
django_blog.id = None
django_blog.save() # django_blog.pk == 4

需要注意的是：这种方法不会复制相关对象。如果想复制相关对象（类似多对多）的话，需要像下面这样。例如，Entry 与 Author 是多对多关系：

entry = Entry.objects.all()[0] # some previous entry
old_authors = entry.authors.all()
entry.pk = None
entry.save()
entry.authors.set(old_authors)

参考文档：
https://docs.djangoproject.com/en/dev/topics/db/queries/#copying-model-instances

https://stackoverflow.com/questions/4733609/how-do-i-clone-a-django-model-instance-object-and-save-it-to-the-database