实体框架 - “映射片段中的问题”-error。帮我理解这个错误的解释 [英] Entity framework - "Problem in mapping fragments"-error. Help me understand the explanations of this error

问题描述

错误3007：从186行开始的片段中的问题：非主键列[WheelID]正在将两个片段映射到不同的概念侧属性 - 数据不一致是可能的，因为相应的概念侧属性可以独立修改。

Error 3007: Problem in Mapping Fragments starting at lines 186, 205: Non-Primary-Key column(s) [WheelID] are being mapped in both fragments to different conceptual side properties - data inconsistency is possible because the corresponding conceptual side properties can be independently modified.

我在Web上找到了几个描述这个错误的地方，但是我根本不了解它们。 （困惑的笑脸在这里）

I found several places on the web describing this error, but I simply don't understand them. (confused smiley goes here)

一个

Two

三个

四个

这里有一些非常重要的东西，我一定是错过了。你能解释一下，以便我明白吗？可能使用我的现实生活中的例子？

There is something pretty fundamental here, I must be missing. Can you explain it, so that I understand it? Maybe using my real life example below?

替代文字http://i39.tinypic.com/2hppnoo.jpg

外键1：N Wheels.Id - > Slices.WheelId

Foreign key 1:N Wheels.Id -> Slices.WheelId

我将它们添加到实体框架中，WheelId在Slices-entity中不可见。

I add them to entity framework, and WheelId is not visible in the Slices-entity.

alt text http://i43.tinypic.com/287hq87.jpg

做一些解决方法（在将表添加到EF之前删除数据库中的关系 - 然后重新创建它并更新EF）我设法使WheelId保留在Slices中，但是我得到了顶部提到的错误。 / p>

Doing some workaround (deleting the relationship from the db before adding tables to EF - then re-creating it and updating EF) I managed to get the WheelId to stay in Slices, but then I get the error mentioned at the top.

推荐答案

由于Slices.WheelId是FK，因此您无法在客户端模型（期间）中公开。有一些方法可以获得价值。

Since Slices.WheelId is an FK, you cannot expose it in your client model, period. There are ways to get the value, though.

var wheelId = someSlice.Wheels.ID;

更新在EF 4中，您可以使用FK关联而不是独立协会。

Update In EF 4 you can do this by using FK Associations instead of independent associations.

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