The EntityContainer name must be unique. An Entity

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

If you are using web deployment from Visual Studio sometimes doesn't delete the old dlls. I had the same problem, change to Web Deployment Package and didn't give me problems.

Answer 2

I had a same problem in my asp.net website, to resolve the problem I purposely added compile time error in one of the cs file in the app code by removing a semicolon, then I rectified the compilation problem by adding semicolon again.

This process caused application to compile again.After this error got vanished.

Answer 3

I just ran into this. It looks like somehow Entity Framework got into a bad state in terms of what tables it thought it needed to add.

Normally EF will not recognize that a new table has to be created until you put the line

public virtual DbSet<NewTable> NewTable { get; set; }

inside your context class.

However, EF somehow got into a bad state where the mere presence of the NewTable class in my solution was triggering it to think that it needed to generate that table. So by the time the above line in the context triggered it to create a NewTable table, it already thought it had done it, hence the error about duplicate entities.

I just removed the NewTable class from my solution, commented things out so it would compile again (thankfully there wasn't too much of this), then added a new migration to make sure it was blank as it should have been. Then once things were back into a more predictable state, I re-added the NewTable class back into the solution and adding the migration worked fine.

Answer 4

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.

Answer 5

In my case, probably after merging a version back, my startup project file (csproj) got corrupted.

Al the Entity classes where added:

<Compile Include="Class.cs">
  <DependentUpon>MyModel.tt</DependentUpon>
</Compile>

After removing all relevant entries by hand the problem was solved.

Answer 6

I renamed my project but the old file was still in the bin folder. I just had to delete the old DLL from the bin folder.