edmx validation throws an error about collide primary key

问题

I have 3 entities: BaseUser, AuthenticationUser and User. AuthenticationUser inherit from BaseUser and User inherit from AuthenticationUser. User entity has scalar property of type Binary (photo) so I would like to split the User entity into User and UserPhoto.

I did exactly what this nice article sais: http://www.deveducate.com/blog/post/2010/12/14/Entity-Framework-Modeling-Table-Splitting.aspx

Here is an image of my edmx:

When I validate the edmx I keep getting this error:

Error 3033: Problem in mapping fragments starting at line 13058:EntitySets 'UserPhotoes' and 'BaseUsers' are both mapped to table 'T_USER'. Their primary keys may collide.

What is the meanning of this error?
Any idea how to fix this?

来源：https://stackoverflow.com/questions/11235092/edmx-validation-throws-an-error-about-collide-primary-key