如何使用声明式创建一对一关系 [英] How to create one-to-one relationships with declarative

问题描述

我有两个表，foo 和 bar，我希望 foo.bar_id 链接到 bar.问题在于，这是一种单向的一对一关系.bar 必须对 foo 一无所知.对于每个 foo，将只有一个 bar.

I have two tables, foo and bar, and I want foo.bar_id to link to bar. The catch is that this is a one-way one-to-one relationship. bar must not know anything about foo. For every foo, there will be one and only one bar.

理想情况下，选择 foo 后，我可以执行以下操作:

Ideally, after selecting a foo, I could do something like this:

myfoo.bar.whatever = 5 

如何做到这一点?

推荐答案

如果您想要真正的一对一关系，您还必须在关系定义中使用uselist=False".

If you want a true one-to-one relationship, you also have to use the "uselist=False" in your relationship definition.

bar_id = Column(Integer, ForeignKey(Bar.id))
bar = relationship(Bar, uselist=False)

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