C# - Entity Framework - The EntityContainer name must be unique. An EntityContainer with the name 'Entities' is already defined.

Question

For a little background:

I have a DLL project with the following structure:

Rivworks.Model (project)  
  \Negotiation (folder)  
      Model.edmx (model from DB #1)  
  \NegotiationAutos (folder)  
      Model.edmx (model from DB #2)  

I have moved the connection strings from this project's app.config to the web.config file. They are not in the ConnectionString section. Rather, I have a static class that consumes part of the web.config and exposes them to my app as AppSettings.[settingName].

<FeedAutosEntities_connString>metadata=res://*/;provider=System.Data.SqlClient;provider connection string='Data Source=db4;Initial Catalog=RivFeeds;Persist Security Info=True;User ID=****;Password=&quot;****&quot;;MultipleActiveResultSets=True'</FeedAutosEntities_connString>
<RivWorkEntities_connString>metadata=res://*/NegotiationAutos.NegotiationAutos.csdl|res://*/NegotiationAutos.NegotiationAutos.ssdl|res://*/NegotiationAutos.NegotiationAutos.msl;provider=System.Data.SqlClient;provider connection string='Data Source=db2;Initial Catalog=RivFramework_Dev;Persist Security Info=True;User ID=****;Password=&quot;****&quot;;MultipleActiveResultSets=True'</RivWorkEntities_connString>

I have 2 classes, one for each Context and they look like this:

namespace RivWorks.Model
{
    public class RivWorksStore
    {
        private RivWorks.Model.Negotiation.Entities _dbNegotiation;

        public RivWorksStore(string connectionString, string metadata, string provider)
        {
            EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder();
            entityBuilder.ConnectionString = connectionString;
            entityBuilder.Metadata = "res://*/";    // metadata;
            //entityBuilder.Provider = provider;
            _dbNegotiation = new RivWorks.Model.Negotiation.Entities(entityBuilder.ConnectionString);
        }

        public RivWorks.Model.Negotiation.Entities NegotiationEntities()
        {
            return _dbNegotiation;
        }
    }
}

namespace RivWorks.Model
{
    public class FeedStoreReadOnly
    {
        private RivWorks.Model.NegotiationAutos.Entities _dbFeed;

        public FeedStoreReadOnly(string connectionString, string metadata, string provider)
        {
            EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder();
            entityBuilder.ConnectionString = connectionString;
            entityBuilder.Metadata = "res://*/";    // metadata;
            //entityBuilder.Provider = provider;
            _dbFeed = new RivWorks.Model.NegotiationAutos.Entities(entityBuilder.ConnectionString);
        }

        public RivWorks.Model.NegotiationAutos.Entities ReadOnlyEntities()
        {
            return _dbFeed;
        }
    }
}

You will note that the MetaData is being rewritten to a short version.

When I comment out that line in each class I get this error:

Unable to load the specified metadata resource.

When I leave that line in in each class I get this error:

Schema specified is not valid. Errors:

Negotiation.Model.csdl(3,4) : error 0019: The EntityContainer name must be unique. An EntityContainer with the name 'Entities' is already defined.

I know it is something simple, something obvious. Any suggestions welcome...

Answer 1

Your two EDMX files probably have the same entity container name. You need to change (at least) one of them.

In the GUI designer, open Model Browser. Look for a node that says "EntityContainer: Entities". Click it. In Properties, change Name to something else. Save and rebuild.