python - 在 Django 中，什么是一对一关系？

Question

我一直在使用外键。

Answer 1

一对一关系是两个实体之间在两个方向上的唯一关系。 IE。对于一个实体 A，只存在一个实体 B，反之亦然。

documentation说:

Conceptually, this is similar to a ForeignKey with unique=True, but the "reverse" side of the relation will directly return a single object.

This is most useful as the primary key of a model which "extends" another model in some way; Multi-table inheritance is implemented by adding an implicit one-to-one relation from the child model to the parent model, for example.