diff --git a/src/Microsoft.Data.Domain.EntityFramework/Model/ModelProducer.cs b/src/Microsoft.Data.Domain.EntityFramework/Model/ModelProducer.cs
index 13deab0c..2311e4c0 100644
--- a/src/Microsoft.Data.Domain.EntityFramework/Model/ModelProducer.cs
+++ b/src/Microsoft.Data.Domain.EntityFramework/Model/ModelProducer.cs
@@ -71,11 +71,19 @@ public class ModelProducer : IModelProducer
                 .ObjectContext.MetadataWorkspace;
             var namespaceName = efModel.GetItems<EntityType>(DataSpace.CSpace)
                 .Select(t => efModel.GetObjectSpaceType(t).NamespaceName)
-                .Distinct().SingleOrDefault();
+                .GroupBy(nameSpace => nameSpace)
+                .Select(group => new
+                {
+                    NameSpace = group.Key,
+                    Count = group.Count(),
+                })
+                .OrderByDescending(nsItem => nsItem.Count)
+                .Select(nsItem => nsItem.NameSpace)
+                .FirstOrDefault();
             if (namespaceName == null)
             {
-                // TODO: support multiple schemas
-                throw new NotSupportedException();
+                // When dbContext has not a namespace, just use its type name as namespace.
+                namespaceName = dbContext.GetType().Namespace ?? dbContext.GetType().Name;
             }
 
             var efEntityContainer = efModel.GetItems<
diff --git a/src/Microsoft.Data.Domain/DomainConfiguration.cs b/src/Microsoft.Data.Domain/DomainConfiguration.cs
index 0165881d..7a338e3d 100644
--- a/src/Microsoft.Data.Domain/DomainConfiguration.cs
+++ b/src/Microsoft.Data.Domain/DomainConfiguration.cs
@@ -20,6 +20,7 @@
 
 using System;
 using System.Collections;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -76,7 +77,7 @@ public class DomainConfiguration : PropertyBag
     {
         private static readonly DomainConfiguration s_global = new DomainConfiguration();
         private static readonly IDictionary<object, DomainConfiguration> s_configurations =
-            new Dictionary<object, DomainConfiguration>();
+            new ConcurrentDictionary<object, DomainConfiguration>();
 
         private readonly IDictionary<Type, object> _singletons =
             new Dictionary<Type, object>();
diff --git a/src/Microsoft.Data.Domain/Model/DomainModel.cs b/src/Microsoft.Data.Domain/Model/DomainModel.cs
index cecd9484..f5ad6407 100644
--- a/src/Microsoft.Data.Domain/Model/DomainModel.cs
+++ b/src/Microsoft.Data.Domain/Model/DomainModel.cs
@@ -18,10 +18,13 @@
 // OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-using System.Collections.Generic;
-using System.Linq;
 using Microsoft.OData.Edm;
 using Microsoft.OData.Edm.Annotations;
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
 
 namespace Microsoft.Data.Domain.Model
 {
@@ -30,7 +33,8 @@ namespace Microsoft.Data.Domain.Model
     // to elements that are not supposed to be visible.
     internal class DomainModel : IEdmModel
     {
-        private IDictionary<string, DomainEntityContainer> _entityContainers;
+        private readonly Lazy<ConcurrentDictionary<string, DomainEntityContainer>> _entityContainers =
+            new Lazy<ConcurrentDictionary<string, DomainEntityContainer>>(LazyThreadSafetyMode.PublicationOnly);
 
         public DomainModel(DomainConfiguration configuration, IEdmModel model)
         {
@@ -204,22 +208,8 @@ private bool IsVocabularyAnnotatableVisible(
         private DomainEntityContainer GetDomainEntityContainer(
             IEdmEntityContainer entityContainer)
         {
-            if (this._entityContainers == null)
-            {
-                this._entityContainers = new Dictionary<
-                    string, DomainEntityContainer>();
-            }
-            DomainEntityContainer domainEntityContainer = null;
-            if (!this._entityContainers.TryGetValue(
-                    entityContainer.FullName(),
-                    out domainEntityContainer))
-            {
-                domainEntityContainer = new DomainEntityContainer(
-                    this, entityContainer);
-                this._entityContainers.Add(
-                    entityContainer.FullName(),
-                    domainEntityContainer);
-            }
+            var domainEntityContainer = this._entityContainers.Value.GetOrAdd(
+                entityContainer.FullName(), name => new DomainEntityContainer(this, entityContainer));
             return domainEntityContainer;
         }
     }