实体框架是否可以在主键和外键之间添加关联 [英] Entity Framework Is it possible to add an ASSOCIATION between Primary Keys and a Foreign Key

问题描述

我的EDMX上有以下实体:-

I've got the following entities on my EDMX :-

这两个实体是由从数据库更新模型生成的.

These two entites were generated by Update Model From Database.

现在，请注意我国是如何具有以下主键的:-

Now, notice how my country has the following primary key :-

名称& IsoCode

这是因为按名称和IsoCode，每个国家/地区在系统中都是唯一的.

this is because each country is UNIQUE in the system by Name and IsoCode.

现在，与我的国家...相似.主键是:-

Now, with my States ... it's similar. Primary Key is :-

名称& CountryId

每个州在名称和国家/地区上都是唯一的.

Each state is unique by name and per country.

现在，国家/地区的外键是一个CountryId.这是sql:-

Now, the Foreign Key for States is a CountryId. This is the sql :-

ALTER TABLE [dbo].[States]  WITH CHECK ADD 
        CONSTRAINT [FK_States_Countries] FOREIGN KEY([CountryId])
REFERENCES [dbo].[Countries] ([CountryId])
ON UPDATE CASCADE
GO

ALTER TABLE [dbo].[States] CHECK CONSTRAINT [FK_States_Countries]
GO

非常简单的东西.

但是EntityFramework不喜欢它:(假设我需要将State实体的某些属性连接到Country实体的两个主键属性.

BUT EntityFramework doesn't like it :( It's assuming that i need to connect some properties from State entity to both primary key properties in the Country entity.

是否可以在Country.CountryId<-> State.CountryId ...上添加Country和State之间的关联，就像我已经映射到数据库中一样?

干杯;)

推荐答案

在EF(3.5和4.0)中，FK必须指向主键.

In EF (3.5 and 4.0) FKs MUST point to Primary Keys.

但是您似乎正在尝试指向候选关键字(即[Countries].[CountryId]

But you appear to be attempting to point to a Candidate Key (i.e. [Countries].[CountryId]

我知道这是EF团队正在考虑的下一个版本:)

I know that this is something the EF team are considering for the next version though :)

希望这会有所帮助

亚历克斯

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