实体框架 - 手动添加导航属性 [英] Entity Framework - Add Navigation Property Manually

问题描述

我从我的数据库生成了一个实体框架模型 (4.0).我没有设计数据库，对schema没有任何控制权，但是有几个表没有定义外键约束，但是定义了一个隐式关系.

I generated an Entity Framework Model (4.0) from my database. I did not design the database and do not have any control over the schema, but there are a few tables that do not have foreign key constraints defined, but there is an implicit relationship defined.

例如:

我有一个名为 People 的表，其中包含以下列:性别ID种族ID

I have a table called People that has the following columns: GenderID RaceID

Gender 和 Race 都有表，但 People 表中没有外键.

There are tables for both Gender and Race but there is no foreign key in the People table.

当我导入模型时，它没有为这些关系添加导航属性.我尝试手动添加它，但 From Role 和 To Role 被禁用.我不确定如何自己添加关系.我该怎么做?

When I imported the model it did not add Navigation Properties for these relationships. I tried to add it manually but From Role and To Role are disabled. I'm not sure how to add the relationship myself. How do I do this?

推荐答案

是的 - 没那么简单.

Yup - it's not that straightforward.

这就是你要做的:

1 - 右键单击​​设计器，添加 -> 关联

1 - Right click on the designer, Add -> Association

2 - 设置关联和基数(人员 *..1 性别，人员 *..1 种族)

2 - Setup the association and cardinalities (People *..1 Gender, People *..1 Race)

3 - 进入模型浏览器 -> 关联

4 - 右键单击​​您新创建的关联，单击属性

4 - Right click on your newly created associations, click Properties

5 - 在这里您需要为密钥和级联选项设置端点.确保您获得正确的端点.您还可以在此处为隐式导航属性设置引用约束.

5 - Here you need to setup the endpoints for the key and cascade options. Make sure you get the endpoints correct. You can also setup a referential constraint here for your implicit navigational property.

6 - 将导航属性映射到相关表/字段.

6 - Map the navigational property to the relevant tables/fields.

7 - 验证您的模型，交叉手指.

7 - Validate your model, cross your fingers.

希望这会有所帮助.

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