如何仅使用Key设置ReferenceProperty,而不是获取Model

Question

考虑到数据存储区中模型的关键,我希望能够在不加载模型本身的情况下设置referenceproperty(因为我不需要该信息).

例如:

class Book(db.Model):
    author = db.StringProperty()
    title = db.StringProperty()

class Review(db.Model):
    book = db.ReferenceProperty(Book)
    description = db.StringProperty()

假设我已经拥有了一个Book(调用它bookKey)的键,但我没有相应的Book对象本身,有没有办法做相当于

review = Review()
review.description = "It was ok, but I would recommend it for insomniacs."
review.book = bookKey

或者我需要

book = Book.get(bookKey) #I don't want this datastore access
                         #as I don't need the book object.
review = Review()
review.description = "It was ok, but I would recommend it for insomniacs."
review.book = book

我找到了从ReferenceProperty使用中提取密钥和ID的方法get_value_for_datastore,但我是在"设置"之后.

Answer 1

review.book = bookKey 将工作得很好,并设置referenceproperty而不提取模型.