public void OnTypeCreation(MetadataContainer metadataContainer) { metadataContainer.Entity <Foo>().Projection(x => x.Id2).IsKey(); metadataContainer.Add(new FooMetadata()); metadataContainer.Entity <Bar>().Projection(x => x.FooSet).Association().WithName("MyAssociation"). WithThisKey(x => x.Id2, x => x.Id).WithOtherKey(x => x.Id2, x => x.Id); }