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

I have found a way to save multiple containers with the same name (namespaced of course).

In EF5 and VS2012 you can set three different namespaces. First you can click on the edmx file in the solution browser and in the properties windows you can set the "Custom Tool Namespace", you can click on the *.Context.tt file right below the edmx and set another namespace there, and finally thanks to a lead from Mr Stuntz awesome answer I realized that by opening the edmx file and clicking in the white space you get another namespace field under Schema in the properties window.

Think we're done, not quite, I know you can see the Entity Container Name field and will try to change the name there but that doesn't seem to work, you get a little error that pops up. Ensure that all your edmx files have an individual namespace there. (I ensured I had a unique namespace in all three places)

Then go to your Model Browser and right click on EntityContainer: Entity to go to properties and change the name of your container(s). From that window with the namespace set everywhere I was able to get multiple contexts with the same name. I was dealing with things like blahcontext and blahcontextcontainer all of a sudden even though they were in different folders.

When you see that its a namespace problem. Or lack thereof.

Answer 2

To solve the issue Entity 6.2.0, VS 2017, single edmx

I changed the name of my model.edmx to another name, built the project, then changed it back to the original name.

Answer 3

I had the problem too but my solution was to clean the bin directory and then remove the connection string with the entity container name. Then I could rename my entities and put back the connection string.

Answer 4

In my case, the problem was caused by my connection string in Web.config being named the same thing as my entities container class.

Change

<add name="ConflictingNameEntities" connectionString="metadata=res://*/blahblah

to

<add name="ConflictingNameEntitiesConnection" connectionString="metadata=res://*/blahblah

and regenerate the container class by right-clicking ConflictingNameModel.Context.tt in Solution Explorer and clicking "Run Custom Tool".

Answer 5

Hijacking this, since it is the top Google result for the error message.

In case anyone else encounters this while only using a single model/context: I once ran into this problem because the assembly containing the model/context was renamed and a copy with the previous name remained in the bin directory of the application. The solution was to delete the old assembly file.

Answer 6

The other cause of this problem, your add model in any solution project and change your model project.

--PROJECT A --> MODEL.EDMX

--- WEB CONFIG -->Entity Connection

--PROJECT B

--- WEB CONFIG -->Entity Connection

Later, I think this structure is bad and Change project.

--PROJECT A
using PROJECT.C;
WEB.CONFIG - USE PROJECT C APP.CONFIG CONNECTIONSTRING 

--PROJECT B
using PROJECT.C;
WEB.CONFIG - USE PROJECT C APP.CONFIG CONNECTIONSTRING 

--PROJECT C  (CLASS LIBRARY) --> MODEL.EDMX 
--- APP.CONFIG -->Entity Connection

Everything was fine but I get an error. Error Detail : The EntityContainer name must be unique. An EntityContainer with the name 'Entities' is already defined

Because I forgot change Web.Config files.

OLD WEB.CONFIG

    <add name="donatelloEntities" connectionString="metadata=res://*;provider=System.Data.SqlClient;provider connection string=&quot;data source=.;initial catalog=donatello;persist security info=True;user id=1;password=1;multipleactiveresultsets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />

NEW WEB.CONFIG

 <add name="donatelloEntities" connectionString="metadata=res://*/EntityModel.Model.csdl|res://*/EntityModel.Model.ssdl|res://*/EntityModel.Model.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=.;initial catalog=donatello;user id=sa;multipleactiveresultsets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />

This Problem is Simple but may cause loss of time. I wanted to give an example. I hope is useful.

Thanks.