diff --git a/Achilles.Entities.Sqlite/IEntitySet.cs b/Achilles.Entities.Sqlite/IEntitySet.cs
index b7e6f45..6fe8518 100644
--- a/Achilles.Entities.Sqlite/IEntitySet.cs
+++ b/Achilles.Entities.Sqlite/IEntitySet.cs
@@ -29,6 +29,6 @@ public interface IEntitySet
         /// <returns></returns>
         Type EntityType { get; }
 
-        IEnumerable<TSource> GetSource<TSource>( TSource source ) where TSource : class;
+        //IEnumerable<TSource> GetSource<TSource>( TSource source ) where TSource : class;
     }
 }
diff --git a/Achilles.Entities.Sqlite/Linq/EntityReferenceOfT.cs b/Achilles.Entities.Sqlite/Linq/EntityReferenceOfT.cs
index b15d7b3..11ff013 100644
--- a/Achilles.Entities.Sqlite/Linq/EntityReferenceOfT.cs
+++ b/Achilles.Entities.Sqlite/Linq/EntityReferenceOfT.cs
@@ -17,7 +17,7 @@
 
 namespace Achilles.Entities.Linq
 {
-    public sealed class EntityReference<TEntity> : IEntityReference<TEntity>, IEntityReference
+    public sealed class EntityReference<TEntity> : IEntityReference<TEntity>, IEntityReference, IEntityReferenceSource
         where TEntity : class
     {
         #region Private Fields
@@ -40,6 +40,8 @@ public EntityReference()
 
         #region Public API
 
+        public bool IsLoaded => _isLoaded;
+
         public TEntity Entity
         {
             get
@@ -54,10 +56,11 @@ public TEntity Entity
             }
         }
 
-        // TJT: Make a direct internal property (Source) reference through a compiled lambda expression
-        public void AttachSource( IEnumerable<TEntity> source )
+        public bool HasSource => (_source != null);
+
+        public void SetSource<TSource>( IEnumerable<TSource> source  ) where TSource : class
         {
-            _source = source;
+            _source = source as IEnumerable<TEntity>;
         }
 
         #endregion
diff --git a/Achilles.Entities.Sqlite/Linq/IEntityReference.cs b/Achilles.Entities.Sqlite/Linq/IEntityReference.cs
index 3910da2..cd05bf4 100644
--- a/Achilles.Entities.Sqlite/Linq/IEntityReference.cs
+++ b/Achilles.Entities.Sqlite/Linq/IEntityReference.cs
@@ -8,8 +8,6 @@
 
 #endregion
 
-using System.Collections.Generic;
-
 namespace Achilles.Entities.Linq
 {
     /// <summary>
@@ -17,6 +15,6 @@ namespace Achilles.Entities.Linq
     /// </summary>
     internal interface IEntityReference
     {
-        //void AttachSource<TEntityRef>( IEnumerable<TEntityRef> source ) where TEntityRef: class;
+        // No API
     }
 }
diff --git a/Achilles.Entities.Sqlite/Linq/IEntityReferenceOfT.cs b/Achilles.Entities.Sqlite/Linq/IEntityReferenceOfT.cs
index b512c28..abc44da 100644
--- a/Achilles.Entities.Sqlite/Linq/IEntityReferenceOfT.cs
+++ b/Achilles.Entities.Sqlite/Linq/IEntityReferenceOfT.cs
@@ -10,7 +10,7 @@
 
 namespace Achilles.Entities.Linq
 {
-    public interface IEntityReference<TEntity>
+    public interface IEntityReference<TEntity> where TEntity : class
     {
         /// <summary>
         /// Gets the wrapped entity.
diff --git a/Achilles.Entities.Sqlite/Linq/IEntityReferenceSource.cs b/Achilles.Entities.Sqlite/Linq/IEntityReferenceSource.cs
new file mode 100644
index 0000000..600b566
--- /dev/null
+++ b/Achilles.Entities.Sqlite/Linq/IEntityReferenceSource.cs
@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Achilles.Entities.Linq
+{
+    internal interface IEntityReferenceSource
+    {
+        bool HasSource { get; }
+
+        void SetSource<TSource>( IEnumerable<TSource> source ) where TSource : class;
+    }
+}
diff --git a/Achilles.Entities.Sqlite/Modelling/EntityModel.cs b/Achilles.Entities.Sqlite/Modelling/EntityModel.cs
index dccf1d5..9f05e44 100644
--- a/Achilles.Entities.Sqlite/Modelling/EntityModel.cs
+++ b/Achilles.Entities.Sqlite/Modelling/EntityModel.cs
@@ -22,47 +22,47 @@ public class EntityModel : IEntityModel
     {
         #region Private Fields
 
-        private readonly EntityMappingCollection _entityMappings;
+        private DataContext _context;
+        private EntityMappingCollection _entityMappings;
 
         #endregion
 
         #region Constructor(s)
 
-        public EntityModel( EntityMappingCollection entityMappings )
+        public EntityModel( DataContext context )
         {
-            _entityMappings = entityMappings ?? throw new ArgumentNullException( nameof( entityMappings ) );
+            _context = context;
+            _entityMappings = new EntityMappingCollection( this );
         }
 
         #endregion
 
         #region Public API
 
+        /// <inheritdoc/>
         public IReadOnlyCollection<IEntityMapping> EntityMappings => _entityMappings.Values as IReadOnlyCollection<IEntityMapping>;
 
-        //public IEntityMapping GetOrAddEntityMapping( Type entityType )
-        //{
-        //    IEntityMapping mapping;
-
-        //    if ( !_entityMappings.TryGetValue( entityType, out mapping ) )
-        //    {
-        //        var EntityMappingType = typeof( EntityMapping<> );
-        //        var mapType = EntityMappingType.MakeGenericType( entityType );
-
-        //        mapping = Activator.CreateInstance( mapType ) as IEntityMapping;
-
-        //        _entityMappings[ entityType ] = mapping;
-        //    }
-
-        //    return mapping;
-        //}
-
+        /// <inheritdoc/>
         public IEntityMapping GetEntityMapping<TEntity>() where TEntity : class
         {
             return GetEntityMapping( typeof( TEntity ) );
         }
 
+        /// <inheritdoc/>
         public IEntityMapping GetEntityMapping( Type entityType ) => _entityMappings.GetEntityMapping( entityType );
 
         #endregion
+
+        #region Internal
+
+        internal IEntityMapping GetOrAddEntityMapping( Type entityType ) 
+            => _entityMappings.GetOrAddEntityMapping( entityType );
+
+        internal void TryAddEntityMapping( Type entityType, IEntityMapping entityMapping ) 
+            => _entityMappings.TryAddEntityMapping( entityType, entityMapping );
+
+        internal DataContext DataContext => _context;
+
+        #endregion
     }
 }
diff --git a/Achilles.Entities.Sqlite/Modelling/EntityModelBuilder.cs b/Achilles.Entities.Sqlite/Modelling/EntityModelBuilder.cs
index 365abb0..bd0d292 100644
--- a/Achilles.Entities.Sqlite/Modelling/EntityModelBuilder.cs
+++ b/Achilles.Entities.Sqlite/Modelling/EntityModelBuilder.cs
@@ -19,10 +19,12 @@
 namespace Achilles.Entities.Modelling
 {
     /// <summary>
-    /// <see cref="IEntityModelBuilder"/> implementation of the fluent builder inteface for relational database modelling.
+    /// <see cref="IEntityModelBuilder"/> implementation of the fluent builder inteface for entity data modelling.
     /// </summary>
     public class EntityModelBuilder : IEntityModelBuilder
     {
+        private DataContext _context;
+
         #region Constructor(s)
 
         /// <summary>
@@ -30,15 +32,15 @@ public class EntityModelBuilder : IEntityModelBuilder
         /// </summary>
         public EntityModelBuilder()
         {
-            EntityMappings = new EntityMappingCollection();
         }
 
         #endregion
 
-        #region Public Properties
+        #region Private Properties
 
-        /// <inheritdoc/>
-        private EntityMappingCollection EntityMappings { get; }
+        private EntityModel Model { get; set; }
+
+        //private EntityMappingCollection EntityMappings => Model.EntityMappings;
 
         #endregion
 
@@ -47,7 +49,7 @@ public EntityModelBuilder()
         /// <inheritdoc/>
         public void Entity<TEntity>( Action<IEntityMappingBuilder<TEntity>> action ) where TEntity : class
         {
-            var builder = new EntityMappingBuilder<TEntity>( EntityMappings );
+            var builder = new EntityMappingBuilder<TEntity>( Model );
 
             action( builder );
 
@@ -57,25 +59,26 @@ public void Entity<TEntity>( Action<IEntityMappingBuilder<TEntity>> action ) whe
         /// <inheritdoc />
         public IEntityModel Build( DataContext context )
         {
+            _context = context;
+
+            Model = new EntityModel( context );
+
             // TJT: Should all entities be added in the user's data context constructor?
             // What should happen if an entity is referenced during model building that is
             // not in the context?
 
             foreach ( var entitySetType in context.EntitySets.Keys )
             {
-                EntityMappings.GetOrAddEntityMapping( entitySetType );
+                Model.GetOrAddEntityMapping( entitySetType );
             }
 
             context.OnModelBuilding( this );
 
-            // TODO: Model Validation...
-
             // The model entity mappings have now been configured.
             // Resolve Entity references and validate the model. 
-
             ResolveMappingsAndValidateModel();
 
-            return new EntityModel( EntityMappings );
+            return Model;
         }
 
         #endregion
@@ -86,12 +89,18 @@ private void AddEntityMapping<TEntity>( EntityMappingBuilder<TEntity> entityMapp
         {
             var EntityMapping = entityMappingBuilder.Build();
 
-            EntityMappings.TryAddEntityMapping( typeof( TEntity ), EntityMapping );
+            Model.TryAddEntityMapping( typeof( TEntity ), EntityMapping );
         }
 
         private void ResolveMappingsAndValidateModel()
         {
+            foreach ( var entityMapping in Model.EntityMappings )
+            {
+                // TJT: Better name?
+                entityMapping.Compile();
+            }
 
+            // TODO: Model Validation...
         }
 
         #endregion
diff --git a/Achilles.Entities.Sqlite/Modelling/IEntityModel.cs b/Achilles.Entities.Sqlite/Modelling/IEntityModel.cs
index 7574fb5..f429388 100644
--- a/Achilles.Entities.Sqlite/Modelling/IEntityModel.cs
+++ b/Achilles.Entities.Sqlite/Modelling/IEntityModel.cs
@@ -26,8 +26,6 @@ public interface IEntityModel
         /// <returns>A read only collection of <see cref="IEntityMapping"/>.</returns>
         IReadOnlyCollection<IEntityMapping> EntityMappings { get; }
 
-        //IEntityMapping GetOrAddEntityMapping( Type entityType );
-
         /// <summary>
         /// Gets an entity mapping by entity type.
         /// </summary>
@@ -36,7 +34,7 @@ public interface IEntityModel
         IEntityMapping GetEntityMapping( Type entityType );
 
         /// <summary>
-        ///  TODO
+        /// Gets an entity mapping by the generic TEntity type.
         /// </summary>
         /// <typeparam name="TEntity"></typeparam>
         /// <returns></returns>
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/ColumnAccessor.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/ColumnAccessor.cs
new file mode 100644
index 0000000..dd49e4b
--- /dev/null
+++ b/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/ColumnAccessor.cs
@@ -0,0 +1,30 @@
+#region Copyright Notice
+
+// Copyright (c) by Achilles Software, All rights reserved.
+//
+// Licensed under the MIT License. See License.txt in the project root for license information.
+//
+// Send questions regarding this copyright notice to: mailto:todd.thomson@achilles-software.com
+
+#endregion
+
+#region Namespaces
+
+using System.Reflection;
+
+#endregion
+
+namespace Achilles.Entities.Modelling.Mapping.Accessors
+{
+    internal class ColumnAccessor<TEntity, TValue> : MemberAccessor<TEntity,TValue>
+        where TEntity : class
+    {
+        private readonly MemberInfo _columnInfo;
+
+        public ColumnAccessor( MemberInfo columnInfo )
+            : base( columnInfo )
+        {
+            _columnInfo = columnInfo;
+        }
+    }
+}
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/EntityCollectionAccessor.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/EntityCollectionAccessor.cs
new file mode 100644
index 0000000..aca1db2
--- /dev/null
+++ b/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/EntityCollectionAccessor.cs
@@ -0,0 +1,28 @@
+#region Copyright Notice
+
+// Copyright (c) by Achilles Software, All rights reserved.
+//
+// Licensed under the MIT License. See License.txt in the project root for license information.
+//
+// Send questions regarding this copyright notice to: mailto:todd.thomson@achilles-software.com
+
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Text;
+
+namespace Achilles.Entities.Modelling.Mapping.Accessors
+{
+    internal class EntityCollectionAccessor<TEntity, TValue> : MemberAccessor<TEntity,TValue>
+    {
+        MemberInfo _entityCollectionInfo;
+
+        public EntityCollectionAccessor( MemberInfo entityReferenceInfo )
+            : base( entityReferenceInfo )
+        {
+            _entityCollectionInfo = entityReferenceInfo;
+        }
+    }
+}
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/EntityReferenceAccessor.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/EntityReferenceAccessor.cs
new file mode 100644
index 0000000..13e864e
--- /dev/null
+++ b/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/EntityReferenceAccessor.cs
@@ -0,0 +1,62 @@
+#region Copyright Notice
+
+// Copyright (c) by Achilles Software, All rights reserved.
+//
+// Licensed under the MIT License. See License.txt in the project root for license information.
+//
+// Send questions regarding this copyright notice to: mailto:todd.thomson@achilles-software.com
+
+#endregion
+
+#region Namespaces
+
+using Achilles.Entities.Linq;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+
+#endregion
+
+namespace Achilles.Entities.Modelling.Mapping.Accessors
+{
+    internal class EntityReferenceAccessor<TEntity, TValue> : MemberAccessor<TEntity,TValue>
+        where TEntity : class
+    {
+        MemberInfo _entityReferenceInfo;
+        EntityReference<TEntity> _entityReference;
+
+        public EntityReferenceAccessor( MemberInfo entityReferenceInfo )
+            : base( entityReferenceInfo )
+        {
+            _entityReferenceInfo = entityReferenceInfo;
+        }
+
+        public Type EntityType => typeof( TEntity );
+
+        public override object GetValue( TEntity entity )
+        {
+            return base.GetValue( entity );
+        }
+
+        public override void SetValue( TEntity entity, object value )
+        {
+            // The base.GetValue gets the entityReference<> class
+            var entityReference = base.GetValue( entity ) as IEntityReferenceSource;
+
+            //Type entityReferencePropertyType = entityReferenceProperty.GetType();
+
+            //// Get the EntitySet<TEntity>
+            //var entityReference = entityReferencePropertyType.GetGenericArguments().First();
+            //var entitySet = _context.EntitySets[ entityReference ];
+
+
+            if ( !entityReference.HasSource )
+            {
+                entityReference.SetSource( value as IEnumerable<TEntity> );
+            }
+
+            //base.SetValue( entity, value );
+        }
+    }
+}
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/ForeignKeyAccessor.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/ForeignKeyAccessor.cs
new file mode 100644
index 0000000..8c2225b
--- /dev/null
+++ b/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/ForeignKeyAccessor.cs
@@ -0,0 +1,30 @@
+#region Copyright Notice
+
+// Copyright (c) by Achilles Software, All rights reserved.
+//
+// Licensed under the MIT License. See License.txt in the project root for license information.
+//
+// Send questions regarding this copyright notice to: mailto:todd.thomson@achilles-software.com
+
+#endregion
+
+#region Namespaces
+
+using System.Reflection;
+
+#endregion
+
+namespace Achilles.Entities.Modelling.Mapping.Accessors
+{
+    public class ForeignKeyAccessor<TEntity,TValue> : MemberAccessor<TEntity,TValue>
+        where TEntity : class
+    {
+        private readonly MemberInfo _foreignKeyInfo;
+
+        public ForeignKeyAccessor( MemberInfo foreignKeyInfo )
+            : base( foreignKeyInfo )
+        {
+            _foreignKeyInfo = foreignKeyInfo;
+        }
+    }
+}
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/ColumnAccessor.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/MemberAccessor.cs
similarity index 76%
rename from Achilles.Entities.Sqlite/Modelling/Mapping/ColumnAccessor.cs
rename to Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/MemberAccessor.cs
index 1a7738d..cc11807 100644
--- a/Achilles.Entities.Sqlite/Modelling/Mapping/ColumnAccessor.cs
+++ b/Achilles.Entities.Sqlite/Modelling/Mapping/Accessors/MemberAccessor.cs
@@ -11,38 +11,35 @@
 #region Namespaces
 
 using System;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 
 #endregion
 
-namespace Achilles.Entities.Modelling.Mapping
+namespace Achilles.Entities.Modelling.Mapping.Accessors
 {
-    internal class ColumnAccessor<TEntity> : MemberAccessor
-        where TEntity : class
+    public abstract class MemberAccessor<TEntity, TValue>
     {
-        private readonly MemberInfo _columnInfo;
+        protected Func<TEntity, object> _getter;
+        protected Action<TEntity, object> _setter;
 
-        private Func<TEntity, object> _getter;
-        private Action<TEntity, object> _setter;
-
-        public ColumnAccessor( MemberInfo columnInfo )
-            : base( columnInfo )
+        public MemberAccessor( MemberInfo memberInfo )
         {
-            _columnInfo = columnInfo;
+            MemberInfo = memberInfo ?? throw new System.ArgumentNullException( nameof( memberInfo ) );
 
             CreateGetter();
             CreateSetter();
         }
 
-        public override object GetValue<TMember>( TMember entity ) => _getter( entity as TEntity );
+        protected MemberInfo MemberInfo { get; }
+
+        public virtual object GetValue( TEntity entity ) => _getter( entity );
 
-        public override void SetValue<TMember>( TMember entity, object value ) => _setter( entity as TEntity, value );
+        public virtual void SetValue( TEntity entity, object value ) => _setter( entity, value );
 
         private void CreateGetter()
         {
-            if ( _columnInfo is PropertyInfo propertyInfo )
+            if ( MemberInfo is PropertyInfo propertyInfo )
             {
                 ParameterExpression instance = Expression.Parameter( typeof( TEntity ), "instance" );
 
@@ -52,7 +49,7 @@ private void CreateGetter()
 
                 _getter = Expression.Lambda<Func<TEntity, object>>( conversion, parameters ).Compile();
             }
-            else if ( _columnInfo is FieldInfo field )
+            else if ( MemberInfo is FieldInfo field )
             {
                 ParameterExpression instance = Expression.Parameter( typeof( TEntity ), "instance" );
 
@@ -66,10 +63,10 @@ private void CreateGetter()
 
         private void CreateSetter()
         {
-            if ( _columnInfo is PropertyInfo propertyInfo )
+            if ( MemberInfo is PropertyInfo propertyInfo )
             {
                 var columnPropertySetMethod = propertyInfo.GetSetMethod();
-                var setMethodParameterType = columnPropertySetMethod.GetParameters().First().ParameterType;
+                var setMethodParameterType = columnPropertySetMethod.GetParameters()[0].ParameterType;
 
                 var entityInstanceParameter = Expression.Parameter( typeof( TEntity ), "instance" );
                 var valueParameter = Expression.Parameter( typeof( object ), "value" );
@@ -81,7 +78,7 @@ private void CreateSetter()
                 _setter = Expression.Lambda<Action<TEntity, object>>(
                     body, parameters ).Compile();
             }
-            else if ( _columnInfo is FieldInfo field )
+            else if ( MemberInfo is FieldInfo field )
             {
                 var instanceParameter = Expression.Parameter( typeof( TEntity ), "instance" );
                 var valueParameter = Expression.Parameter( typeof( object ), "value" );
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/Builders/EntityMappingBuilder.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/Builders/EntityMappingBuilder.cs
index 08ad67a..6e1a378 100644
--- a/Achilles.Entities.Sqlite/Modelling/Mapping/Builders/EntityMappingBuilder.cs
+++ b/Achilles.Entities.Sqlite/Modelling/Mapping/Builders/EntityMappingBuilder.cs
@@ -29,7 +29,7 @@ public class EntityMappingBuilder<TEntity> : IEntityMappingBuilder<TEntity> wher
     {
         #region Private Fields
 
-        private EntityMappingCollection _entityMappings;
+        private EntityModel _model;
 
         private readonly List<ColumnMappingBuilder> _columnMappingBuilders = new List<ColumnMappingBuilder>();
         private readonly List<IndexMappingBuilder> _indexMappingBuilders = new List<IndexMappingBuilder>();
@@ -43,11 +43,11 @@ public class EntityMappingBuilder<TEntity> : IEntityMappingBuilder<TEntity> wher
         /// <summary>
         /// Constructs a new EntityMappingBuilder instance. 
         /// </summary>
-        public EntityMappingBuilder( EntityMappingCollection entityMappings )
+        public EntityMappingBuilder( EntityModel model )
         {
-            _entityMappings = entityMappings;
+            _model = model;
             
-            EntityMapping = entityMappings.GetOrAddEntityMapping( EntityType );
+            EntityMapping = model.GetOrAddEntityMapping( EntityType );
         }
 
         #endregion
@@ -168,7 +168,7 @@ public IEntityMapping Build()
 
                 if ( t != EntityType )
                 {
-                    var foreignKeyConstraintMapping = _entityMappings.GetOrAddEntityMapping( t );
+                    var foreignKeyConstraintMapping = _model.GetOrAddEntityMapping( t );
                     foreignKeyConstraintMapping.ForeignKeyMappings.Add( hasManyMapping.ForeignKeyMapping );
                 }
                 else
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/EntityMapping.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/EntityMapping.cs
index 8e755bf..323f377 100644
--- a/Achilles.Entities.Sqlite/Modelling/Mapping/EntityMapping.cs
+++ b/Achilles.Entities.Sqlite/Modelling/Mapping/EntityMapping.cs
@@ -10,6 +10,7 @@
 
 #region Namespaces
 
+using Achilles.Entities.Modelling.Mapping.Accessors;
 using Achilles.Entities.Relational.Modelling.Mapping;
 using System;
 using System.Collections.Generic;
@@ -29,15 +30,24 @@ public class EntityMapping<TEntity> : IEntityMapping where  TEntity : class
     {
         #region Fields
 
+        private EntityModel _model;
+
         private Dictionary<string, MemberInfo> _columnProperties;
         private Dictionary<string, MemberInfo> _foreignKeyProperties;
         private Dictionary<string, MemberInfo> _relationshipProperties;
 
-        //private Dictionary<string, Func<TEntity, object>> ColumnGetters = new Dictionary<string, Func<TEntity, object>>();
-        //private Dictionary<string, Action<TEntity,object>> ColumnSetters = new Dictionary<string, Action<TEntity,object>>();
+        private Dictionary<string, MemberAccessor<TEntity,object>> ColumnAccessors 
+            = new Dictionary<string, MemberAccessor<TEntity,object>>();
+
+        private Dictionary<string, MemberAccessor<TEntity,object>> ForeignKeyAccessors 
+            = new Dictionary<string, MemberAccessor<TEntity, object>>();
 
-        private Dictionary<string, MemberAccessor> ColumnAccessors = new Dictionary<string, MemberAccessor>();
+        private Dictionary<string, MemberAccessor<TEntity, IEnumerable<TEntity>>> EntityReferenceAccessors 
+            = new Dictionary<string, MemberAccessor<TEntity, IEnumerable<TEntity>>>();
 
+        private Dictionary<string, MemberAccessor<TEntity, IEnumerable<TEntity>>> EntityCollectionAccessors 
+            = new Dictionary<string, MemberAccessor<TEntity, IEnumerable<TEntity>>>();
+        
         #endregion
 
         #region Constructor(s)
@@ -45,8 +55,10 @@ public class EntityMapping<TEntity> : IEntityMapping where  TEntity : class
         /// <summary>
         /// Constructs a new instance of <see cref="EntityMapping{TEntity}"/>.
         /// </summary>
-        public EntityMapping()
+        public EntityMapping( EntityModel model )
         {
+            _model = model;
+
             InitializePropertyAndFieldMappings();
         }
 
@@ -54,9 +66,14 @@ public EntityMapping()
 
         #region Public Properties
 
-        public object GetColumn<T>( T entity, string propertyName ) where T : class => ColumnAccessors[ propertyName ].GetValue( entity as TEntity );
+        public object GetColumn<T>( T entity, string propertyName ) where T : class 
+            => ColumnAccessors[ propertyName ].GetValue( entity as TEntity );
 
-        public void SetColumn<T>( T entity, string propertyName, object value ) where T: class => ColumnAccessors[ propertyName ].SetValue( entity as TEntity, value );
+        public void SetColumn<T>( T entity, string propertyName, object value ) where T: class 
+            => ColumnAccessors[ propertyName ].SetValue( entity as TEntity, value );
+
+        public void SetEntityReference<T>( T Entity, string propertyName, object source ) where T : class
+            => EntityReferenceAccessors[ propertyName ].SetValue( Entity as TEntity, source );     
 
         public List<IColumnMapping> ColumnMappings { get; set; } = new List<IColumnMapping>();
 
@@ -76,8 +93,14 @@ public EntityMapping()
 
         #endregion
 
+        #region Internal Properties
+
+        internal EntitySet<TEntity> EntitySet => (EntitySet< TEntity>)_model.DataContext.EntitySets[ EntityType ];
+
+        #endregion
+
         #region Public Methods
-        
+
         public void Compile()
         {
             _columnProperties = ColumnMappings.ToDictionary( m => m.ColumnName, m => m.ColumnInfo, IsCaseSensitive? StringComparer.Ordinal : StringComparer.OrdinalIgnoreCase );
@@ -87,6 +110,8 @@ public void Compile()
 
         #endregion
 
+
+
         #region Private Methods
 
         private void CreateAccessors()
@@ -94,13 +119,32 @@ private void CreateAccessors()
             // Columns...
             foreach ( var columnMapping in ColumnMappings )
             {
-                ColumnAccessors.Add( columnMapping.PropertyName, new ColumnAccessor<TEntity>( columnMapping.ColumnInfo ) );
+                ColumnAccessors.Add( columnMapping.PropertyName, new ColumnAccessor<TEntity,object>( columnMapping.ColumnInfo ) );
             }
-        }
 
+            // Foreign Keys...
+            foreach ( var foreignKeyMapping in ForeignKeyMappings )
+            {
+                ForeignKeyAccessors.Add( foreignKeyMapping.PropertyName, new ForeignKeyAccessor<TEntity, object>( foreignKeyMapping.ForeignKeyProperty ) );
+            }
 
-        private void CreateRelationshipSetters()
-        {
+            // Relationship Mappings...
+            foreach ( var relationshipMapping in RelationshipMappings )
+            {
+                if ( relationshipMapping.IsMany )
+                {
+                    EntityCollectionAccessors.Add(
+                        relationshipMapping.RelationshipProperty.Name,
+                        new EntityCollectionAccessor<TEntity, IEnumerable<TEntity>>( relationshipMapping.RelationshipProperty ) );
+                }
+                else
+                {
+                    EntityReferenceAccessors.Add(
+                        relationshipMapping.RelationshipProperty.Name,
+                        new EntityReferenceAccessor<TEntity, IEnumerable<TEntity>>( relationshipMapping.RelationshipProperty ) );
+
+                }
+            }
         }
 
         /// <summary>
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/EntityMappingCollection.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/EntityMappingCollection.cs
index 7c3ebfb..aa67b76 100644
--- a/Achilles.Entities.Sqlite/Modelling/Mapping/EntityMappingCollection.cs
+++ b/Achilles.Entities.Sqlite/Modelling/Mapping/EntityMappingCollection.cs
@@ -22,16 +22,26 @@ namespace Achilles.Entities.Modelling.Mapping
     /// <summary>
     /// Collection class for entity mappings. 
     /// </summary>
-    public class EntityMappingCollection //: IDictionary<Type,IEntityMapping>
+    internal class EntityMappingCollection
     {
         #region Fields
 
+        private EntityModel _model;
         private ConcurrentDictionary<Type, IEntityMapping> _entityMappings = new ConcurrentDictionary<Type, IEntityMapping>();
 
         #endregion
 
+        #region Constructor(s)
+
+        public EntityMappingCollection( EntityModel model )
+        {
+            _model = model;
+        }
+
+        #endregion
+
         /// <summary>
-        /// TODO:
+        /// Gets an entity type if it is already in the collection or creates and adds the entity to the collection.
         /// </summary>
         /// <param name="entityType"></param>
         /// <returns></returns>
@@ -39,15 +49,12 @@ public IEntityMapping GetOrAddEntityMapping( Type entityType )
         {
             if ( !_entityMappings.TryGetValue( entityType, out IEntityMapping mapping ) )
             {
-                var EntityMappingType = typeof( EntityMapping<> );
-                var mappingType = EntityMappingType.MakeGenericType( entityType );
+                var entityMappingType = typeof( EntityMapping<> );
+                var genericEntityMappingType = entityMappingType.MakeGenericType( entityType );
 
-                mapping = Activator.CreateInstance( mappingType ) as IEntityMapping;
+                mapping = Activator.CreateInstance( genericEntityMappingType, _model ) as IEntityMapping;
 
                 _entityMappings[ entityType ] = mapping;
-
-                // TJT: Review. Perhaps this is better done elsewhere
-                mapping.Compile();
             }
 
             return mapping;
@@ -55,10 +62,12 @@ public IEntityMapping GetOrAddEntityMapping( Type entityType )
 
         public void TryAddEntityMapping( Type entityType, IEntityMapping entityMapping )
         {
+            // TJT: Review this method.
+
             if ( _entityMappings.TryAdd( entityType, entityMapping ) )
             {
                 // Compile the defined mapping into a column <-> member info lookup dictionary.
-                entityMapping.Compile();
+                //entityMapping.Compile();
             }
         }
 
@@ -72,68 +81,9 @@ public IEntityMapping GetEntityMapping( Type entityType )
             throw new ArgumentException( nameof( entityType ) );
         }
 
-        //#region IDictionary Implementation through _EntityMappingpings
-
-        //public IEntityMapping this[ Type key ] { get => ((IDictionary<Type, IEntityMapping>)_entityMappings)[ key ]; set => ((IDictionary<Type, IEntityMapping>)_entityMappings)[ key ] = value; }
-
         public ICollection<Type> Keys => ((IDictionary<Type, IEntityMapping>)_entityMappings).Keys;
 
         public ICollection<IEntityMapping> Values => ((IDictionary<Type, IEntityMapping>)_entityMappings).Values;
 
-        //public int Count => ((IDictionary<Type, IEntityMapping>)_entityMappings).Count;
-
-        //public bool IsReadOnly => ((IDictionary<Type, IEntityMapping>)_entityMappings).IsReadOnly;
-
-        //public void Add( KeyValuePair<Type, IEntityMapping> item )
-        //{
-        //    ((IDictionary<Type, IEntityMapping>)_entityMappings).Add( item );
-        //}
-
-        //public void Clear()
-        //{
-        //    ((IDictionary<Type, IEntityMapping>)_entityMappings).Clear();
-        //}
-
-        //public bool Contains( KeyValuePair<Type, IEntityMapping> item )
-        //{
-        //    return ((IDictionary<Type, IEntityMapping>)_entityMappings).Contains( item );
-        //}
-
-        //public bool ContainsKey( Type key )
-        //{
-        //    return ((IDictionary<Type, IEntityMapping>)_entityMappings).ContainsKey( key );
-        //}
-
-        //public void CopyTo( KeyValuePair<Type, IEntityMapping>[] array, int arrayIndex )
-        //{
-        //    ((IDictionary<Type, IEntityMapping>)_entityMappings).CopyTo( array, arrayIndex );
-        //}
-
-        //public IEnumerator<KeyValuePair<Type, IEntityMapping>> GetEnumerator()
-        //{
-        //    return ((IDictionary<Type, IEntityMapping>)_entityMappings).GetEnumerator();
-        //}
-
-        //public bool Remove( Type key )
-        //{
-        //    return ((IDictionary<Type, IEntityMapping>)_entityMappings).Remove( key );
-        //}
-
-        //public bool Remove( KeyValuePair<Type, IEntityMapping> item )
-        //{
-        //    return ((IDictionary<Type, IEntityMapping>)_entityMappings).Remove( item );
-        //}
-
-        //public bool TryGetValue( Type key, out IEntityMapping value )
-        //{
-        //    return ((IDictionary<Type, IEntityMapping>)_entityMappings).TryGetValue( key, out value );
-        //}
-
-        ////IEnumerator IEnumerable.GetEnumerator()
-        ////{
-        ////    return ((IDictionary<Type, IEntityMapping>)_entityMappings).GetEnumerator();
-        ////}
-
-        //#endregion
     }
 }
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/IEntityMapping.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/IEntityMapping.cs
index ec474f6..3f49987 100644
--- a/Achilles.Entities.Sqlite/Modelling/Mapping/IEntityMapping.cs
+++ b/Achilles.Entities.Sqlite/Modelling/Mapping/IEntityMapping.cs
@@ -42,6 +42,8 @@ public interface IEntityMapping
 
         void SetColumn<T>( T entity, string propertyName, object value ) where T : class;
 
+        void SetEntityReference<T>( T entity, string propertyName, object value ) where T : class;
+
         void Compile();
     }
 }
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/IForeignKeyMapping.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/IForeignKeyMapping.cs
index 82976f7..92c3abe 100644
--- a/Achilles.Entities.Sqlite/Modelling/Mapping/IForeignKeyMapping.cs
+++ b/Achilles.Entities.Sqlite/Modelling/Mapping/IForeignKeyMapping.cs
@@ -30,7 +30,7 @@ public interface IForeignKeyMapping
         string PropertyName { get; }
 
         /// <summary>
-        /// Gets teh Reference key <see cref="MemberInfo"/>.
+        /// Gets the reference key <see cref="MemberInfo"/> property or field.
         /// </summary>
         MemberInfo ReferenceKeyProperty { get; set; }
 
diff --git a/Achilles.Entities.Sqlite/Modelling/Mapping/MemberAccessor.cs b/Achilles.Entities.Sqlite/Modelling/Mapping/MemberAccessor.cs
deleted file mode 100644
index c2d71b0..0000000
--- a/Achilles.Entities.Sqlite/Modelling/Mapping/MemberAccessor.cs
+++ /dev/null
@@ -1,32 +0,0 @@
-#region Copyright Notice
-
-// Copyright (c) by Achilles Software, All rights reserved.
-//
-// Licensed under the MIT License. See License.txt in the project root for license information.
-//
-// Send questions regarding this copyright notice to: mailto:todd.thomson@achilles-software.com
-
-#endregion
-
-#region Namespaces
-
-using System.Reflection;
-
-#endregion
-
-namespace Achilles.Entities.Modelling.Mapping
-{
-    public abstract class MemberAccessor
-    {
-        public MemberAccessor( MemberInfo memberInfo )
-        {
-            MemberInfo = memberInfo ?? throw new System.ArgumentNullException( nameof( memberInfo ) );
-        }
-
-        protected MemberInfo MemberInfo { get; }
-
-        public abstract object GetValue<TMember>( TMember member );
-
-        public abstract void SetValue<TMember>( TMember member, object value );
-    }
-}
diff --git a/Achilles.Entities.Sqlite/Querying/EntityMaterializer.cs b/Achilles.Entities.Sqlite/Querying/EntityMaterializer.cs
index 33a8f49..2cdcfb3 100644
--- a/Achilles.Entities.Sqlite/Querying/EntityMaterializer.cs
+++ b/Achilles.Entities.Sqlite/Querying/EntityMaterializer.cs
@@ -141,6 +141,7 @@ internal object Materialize( IDictionary<string, object> dictionary, object enti
             if ( entity.GetType().IsPrimitive || entity is string )
             {
                 object value;
+
                 if ( !dictionary.TryGetValue( "$", out value ) )
                 {
                     throw new InvalidCastException( "For lists of primitive types, include $ as the name of the property" );
@@ -151,11 +152,6 @@ internal object Materialize( IDictionary<string, object> dictionary, object enti
                 return entity;
             }
 
-            // Once we have the instance we can attach an entity set source to the instance relationship properties
-            var entityMapping = _model.GetEntityMapping( entity.GetType() );
-
-            var relationshipMappings = entityMapping.RelationshipMappings;
-
             var fieldsAndProperties = GetFieldsAndProperties( entity.GetType() );
 
             foreach ( var fieldOrProperty in fieldsAndProperties )
@@ -163,49 +159,6 @@ internal object Materialize( IDictionary<string, object> dictionary, object enti
                 var memberName = fieldOrProperty.Key.ToLower();
                 var memberInfo = fieldOrProperty.Value;
 
-                var relationshipMapping = relationshipMappings.Where( r => r.RelationshipProperty == memberInfo ).FirstOrDefault();
-
-                if ( relationshipMapping != null )
-                {
-                    if ( relationshipMapping.IsMany )
-                    {
-                        //IEntityCollection entityCollection = memberInfo as IEntityCollection;
-                    }
-                    else
-                    {
-                        // First Get the type entity we are materializing
-                        Type entityType = entity.GetType();
-
-                        object entityReferenceProperty;
-
-                        if ( memberInfo.MemberType == MemberTypes.Property )
-                        {
-                            PropertyInfo propertyInfo = memberInfo as PropertyInfo;
-
-                            // Gets the property EntityReference<TEntity> class instance 
-                            entityReferenceProperty = propertyInfo.GetValue( entity );
-                        }
-                        else
-                        {
-                            FieldInfo fieldInfo = memberInfo as FieldInfo;
-
-                            entityReferenceProperty = fieldInfo.GetValue( entity );
-                        }
-
-                        Type entityReferencePropertyType = entityReferenceProperty.GetType();
-
-                        MethodInfo attachSourceMethod = entityReferencePropertyType.GetMethod( "AttachSource" );
-
-                        // Get the EntitySet<TEntity>
-                        var entityReference = entityReferencePropertyType.GetGenericArguments().First();
-                        var entitySet = _context.EntitySets[ entityReference ];
-
-                        attachSourceMethod.Invoke( entityReferenceProperty, new object[] { entitySet } );
-                    }
-
-                    continue;
-                }
-
                 object value;
 
                 // Handle populating simple members on the current type
@@ -288,9 +241,42 @@ internal object Materialize( IDictionary<string, object> dictionary, object enti
                 }
             }
 
+            SetDeferredLoading( entity );
+
             return entity;
         }
 
+        private void SetDeferredLoading ( object entity )
+        {
+            // Once we have the entity instance we can attach an entity set source to the instance relationship properties
+            var entityMapping = _model.GetEntityMapping( entity.GetType() );
+
+            var relationshipMappings = entityMapping.RelationshipMappings;
+
+            foreach (  var relationshipMapping in relationshipMappings )
+            {
+                var foreignKey = relationshipMapping.ForeignKeyMapping;
+
+                if ( relationshipMapping.IsMany )
+                {
+                    //entityMapping.SetEntityCollection(
+                    //    entity,
+                    //    relationshipMapping.RelationshipProperty.Name,
+                    //    relationshipMapping.ForeignKeyMapping );
+                }
+                else
+                {
+                    entityMapping.SetEntityReference( 
+                        entity, 
+                        relationshipMapping.RelationshipProperty.Name,
+                        relationshipMapping.ForeignKeyMapping );
+                }
+
+                continue;
+            }
+
+        }
+
         /// <summary>
         /// Populates the given instance's properties where the IDictionary key property names
         /// match the type's property names case insensitively.