EF4 Poco Issue Mapping Types Same Name Same Assembly Different Namespaces

Question

I am experiencing an issue with EF4 and Proxy Pocos.

I have 2 classes with the same name in the same assembly but different namespaces:

QuoteModels.CashPayment
OrderModels.CashPayment

This compiles fine but at runtime EF throws the following exception:

Schema specified is not valid. Errors: \r\nThe mapping of CLR type to EDM type is ambiguous because multiple CLR types match the EDM type 'CashPayment'. Previously found CLR type 'QuoteModels.CashPayment', newly found CLR type 'OrderModels.CashPayment'

Is there a workaround to have classes with the same name in the same assembly with different namespaces to work with Ef4?

Do I have to give them different names or move them into another assembly?

Answer 1

I've found a work-around. It's a very obvious work-around that is non-ideal, but I think I'm going to call it good enough for us until EF5 comes out to fix this.

Short Answer: Just rename one or both of the ambigous entities Like: 2x Person are renamed to: Personal_Person and Work_Person based on a PersonalContext and a WorkContext.

Long Answer: In our scenario, we're using a DB-first approach (we're rewriting a legacy app with minimal DB changes). Our DB contains hundreds of tables, so rather than using a single EDMX/Context, I'm using multiple EDMX/Contexts (the EDMX has croaked every time I've attempted to add more than half of our tables). However, some tables need to exist in more than one EDMX/Context.

For discussion, let's pretend we have a simple database with the following tables:

• Person
• Family
• Relationship
• Address
• Business
• Employee

Also, for the sake of this discussion, let's assume that ANY table that exists in multiple contexts causes this problem (as I stated in comments to Devart's answer, this is not really true and I don't understand why it sometimes works).

Now let's say we want to create two contexts:

PersonalContext:

• Person
• Family
• Relationship
• Address

WorkContext:

• Person
• Business
• Address
• Employee

In this scenario, both Person and Address will cause our problem. So what we will do in our EDMX mapping is simply rename our entities to Personal_Person/Work_Person and Personal_Address/Work_Address.

As stated, this is very much an obvious work-around that is non-ideal but since EF doesn't take namespacing into account and goes strictly by name (not true identity, simply the name), one option is to put your namespacing inside your name.

Now I'm still debating if I'm going to do it that way or perhaps namespace the name for every entity (Personal_Person, Personal_Family, Personal_Relationship, Personal_Address and Work_Person, Work_Business, Work_Address, and Work_Employee) for both consistency and Intellisense-friendliness (keeping all entities in proper alphabetic order) since really, the namespace belongs before the name instead of after it, but that's a judgement call and not really important to providing a solution to the problem.

I hope this helps!!

Answer 2

Take a look at this post. The Derek's comment seems to deal with the same issue, and he did not receive any answer from Microsoft.

Answer 3

What I did was to delete one of the repeated entities and for the other entity create a partial class that has the properties of the deleted entity

Example:

namespace Namespace1
{
 class Talk
 {
  public int TalkId {get; set;}
 }
}
namespace Namespace2
{
 class Talk
 {
  public int TalkId {get; set;}
  public string SomeExtraInfo {get; set;}
 }
}

Result:

namespace Namespace1
{
 class Talk
 {
  public int TalkId {get; set;}
 }
}
namespace Namespace1
{
 partial class Talk
 {
  public string SomeExtraInfo {get; set;}
 }
}

Hope it helps someone

Answer 4

I just ran into a similar problem. It took me a while to pinpoint the pattern but in my context problems occured when I had two models which both had two of the same entities.

On one of my model I had the following entities ("->" denotes relationship with direction): Users -> Authentication -> Authorization (a user gets authenticated then authorized).

On the other one I had these entities: Authentication -> Authorization -> InvoiceGeneration (an authenticated and authorized user generates an invoice).

Upon running my app with these two models I got the same error as the original poster.

It turned out that, that my problem dissapeared when I removed the Authentication entity from the second model so it seems that EDM to CLR mapper cannot cope with entities who have same kind of "parent" relationships (on both of my models Authorization was "preceded" by Authentication. Sorry for the non-scientific relationship descriptions :)