在实例化模型的EF数据库优先方法中，它无法确定类型之间关联的主要终点

Question

Basically, I have two tables. Principal table let's say "Foo" that has PK column ID of type int, and dependent table "Bar" that has PK column FooID of type int that is also a FK to ID of "Foo".

As I understood, the problem is that dependent type lacks [Foreign Key] attribute on the primary key property. Problem can be resolved on dependent type's side by either specifying [Foreign Key] attribute on PK or specifying [Required] attribute on the navigation property of PK.

I have tried to add [Required] but it didn't help much. Problem was resolved but models couldn't pass validation because of that. I don't want them to be validated because those properties can be null sometimes, at least when I use them to insert to DB. Turning off validation check on SaveChanges() also didn't help because I started to get other weird exceptions.

Now I want to try specifying [ForeignKey] attribute but can't figure out how to make it happen. I don't have experience with T4 (*.tt file). I don't know how to check property if it's a fk and don't know how to get its name. So please help me.

Answer 1

I tried to re-create EDMX and ran some db insertions on a different machine. Strangely, this error does not occur on that machine. Found out recently that EF does not need DataAnnotaions because it uses mappings from XML files not from code from here . So I guess the problem was that my old pc somehow couldn't correctly create EDMX or couldn't use mappings from xml. The cause is not clear to me yet. But the problem was resolved.