The mapping of CLR type to EDM type is ambiguous with EF 6 & 5?

Question

Please any one can help me to fix this error?

Schema specified is not valid. Errors:

The mapping of CLR type to EDM type is ambiguous because multiple CLR types match the EDM type 'City_DAL'. Previously found CLR type 'CeossDAL.City_DAL', newly found CLR type 'CeossBLL.City_DAL'.

The main problem that I have DAL and this contains the EF and BLL and this contains the same classes of the DAL but differ in the namespace and this is what cause the problem

I can't know how to get rid of these problem, can you please help me?

Also I will be appreciated if some one give me sample to use n-tier architecture with EF

Thank you

Answer 1

Don't use classes with the same unqualified name - EF uses only class names to identify the type mapped in EDMX (namespaces are ignored) - it is a convention to allow mapping classes from different namespaces to single model. The solution for your problem is to name your classes in BLL differently.

Answer 2

Workaround: Change a property on one of the two identical classes.

EF matches on class name AND class properties. So I just changed a property name on one of the EF objects, and the error is gone.

As @Entrodus commented on one of the other answers:

EF collision happens only when two classes have the same name AND the same set of parameters.

Answer 3

This MSDN forum question might be helpful. It suggest placing the BLL and DAL classes in separate assemblies.

Answer 4

In some cases this is more of a symptom than the actual problem. For me, it usually pops up when I try to call a function inside a Linq query without calling .ToList() first.

E.g. the error that brought me here was caused because I did this:

var vehicles = DB.Vehicles.Select(x => new QuickSearchResult()
{
    BodyText = x.Make + " " + x.Model + "<br/>"
    + "VIN: " + x.VIN + "<br/>"
    + "Reg: " + x.RegistrationNumber +"<br/>"
    + x.AdditionalInfo
    type = QuickSearchResultType.Vehicle,//HERE. Can't use an enum in an IQueryable.
    UniqueId = x.VehicleID
});

I had to call .ToList(), then iterate through each item and assign the type to it.

Answer 5

For EF 6.x, I found some notes at https://github.com/aspnet/EntityFramework/issues/941 and fixed this in my solution by adding annotation to the EDM type.

I edited the EDMX file manually and changed a line like this:

<EntityType Name="CartItem">

to this:

<EntityType Name="CartItem" customannotation:ClrType="EntityModel.CartItem">

or use this if you have existing type elsewhere:

<EntityType Name="CartItem" customannotation:ClrType="MyApp.CartItem, MyApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">

where EntityModel is the namespace used for my EF model, and MyApp is the namespace of a business object