EF4自身参考与关联0..1 - > 1 [英] EF4 Self referencing with association 0..1 -> 1

问题描述

有很多关于自我引用问题的阅读，但我似乎找不到我的问题的答案。

说我有一个人（A），我想要A有一个合作伙伴，另一个人（B）。当然，这意味着B在人类中有一个伙伴A.你会如何解决这个问题？理想情况下，我只需要做：

  humanA.Partner = humanB; 
  

，并且humanB将自动将manA作为合作伙伴。

$ b $我会以为我可以创造一个人类，并添加一个协会，如：

End1 实体：人类，多重性： 0..1 ，导航属性：合作伙伴

End2 实体：人类，多重性： 0..1

所以，每个人都有零个或一个合作伙伴是人类。

感谢你的时间。

解决方案

1：0..1只有当实体共享主键。这意味着相关实体FK也是其PK。所以自我参考1：0..1不能存在。我想你甚至不能直接在数据库中映射。

There's a lot of reading on self referencing problems, but I can't seem to find an answer to my question.

Say I have a Human(A), and I want A to have a partner, another Human(B). Naturally, it means that B has a partner in human A. How would you solve this? Ideally, I should only have to do:

humanA.Partner = humanB;

and humanB would automatically get humanA as a partner.

I would have thought I could create a Human enity, and add an Association, something like:

End1 Entity:Human, Multiplicity:0..1, Navigation Property:Partner

End2 Entity:Human, Multiplicity:0..1

So, each human has zero or one Partner which is a human.

Thanks for your time.

解决方案

1:0..1 mapping is possible only when entities "share" primary key. It means when the related's entity FK is also its PK. So self referencing 1:0..1 cannot exist. I think you can't even map it in database directly.

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