diff --git a/AmalgamationTool/DynamORM.Amalgamation.cs b/AmalgamationTool/DynamORM.Amalgamation.cs
index dce3fc5..af91981 100644
--- a/AmalgamationTool/DynamORM.Amalgamation.cs
+++ b/AmalgamationTool/DynamORM.Amalgamation.cs
@@ -1840,9 +1840,18 @@ namespace DynamORM
         /// <param name="e">Enumerable containing instances of objects to insert.</param>
         /// <returns>Number of inserted rows.</returns>
         public virtual int Insert<T>(IEnumerable<T> e) where T : class
+        {
+            return Insert(typeof(T), e);
+        }
+
+        /// <summary>Bulk insert objects into database.</summary>
+        /// <param name="t">Type of objects to insert.</param>
+        /// <param name="e">Enumerable containing instances of objects to insert.</param>
+        /// <returns>Number of inserted rows.</returns>
+        public virtual int Insert(Type t, IEnumerable e)
         {
             int affected = 0;
-            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(typeof(T));
+            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(t);
 
             if (mapper != null)
             {
@@ -1871,9 +1880,9 @@ namespace DynamORM
                             }
                         }
                         else
-                            PrepareBatchInsert<T>(mapper, cmd, parameters);
+                            PrepareBatchInsert(t, mapper, cmd, parameters);
 
-                        foreach (T o in e)
+                        foreach (var o in e)
                         {
                             foreach (KeyValuePair<IDbDataParameter, DynamicPropertyInvoker> m in parameters)
                                 m.Key.Value = m.Value.Get(o);
@@ -1938,9 +1947,18 @@ namespace DynamORM
         /// <param name="e">Enumerable containing instances of objects to update.</param>
         /// <returns>Number of updated rows.</returns>
         public virtual int Update<T>(IEnumerable<T> e) where T : class
+        {
+            return Update(typeof(T), e);
+        }
+
+        /// <summary>Bulk update objects in database.</summary>
+        /// <param name="T">Type of objects to update.</param>
+        /// <param name="e">Enumerable containing instances of objects to update.</param>
+        /// <returns>Number of updated rows.</returns>
+        public virtual int Update(Type t, IEnumerable e)
         {
             int affected = 0;
-            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(typeof(T));
+            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(t);
 
             if (mapper != null)
             {
@@ -1969,9 +1987,9 @@ namespace DynamORM
                             }
                         }
                         else
-                            PrepareBatchUpdate<T>(mapper, cmd, parameters);
+                            PrepareBatchUpdate(t, mapper, cmd, parameters);
 
-                        foreach (T o in e)
+                        foreach (var o in e)
                         {
                             foreach (KeyValuePair<IDbDataParameter, DynamicPropertyInvoker> m in parameters)
                                 m.Key.Value = m.Value.Get(o);
@@ -2004,9 +2022,18 @@ namespace DynamORM
         /// <param name="e">Enumerable containing instances of objects to update or insert.</param>
         /// <returns>Number of updated or inserted rows.</returns>
         public virtual int UpdateOrInsert<T>(IEnumerable<T> e) where T : class
+        {
+            return UpdateOrInsert(typeof(T), e);
+        }
+
+        /// <summary>Bulk update or insert objects into database.</summary>
+        /// <param name="t">Type of objects to update or insert.</param>
+        /// <param name="e">Enumerable containing instances of objects to update or insert.</param>
+        /// <returns>Number of updated or inserted rows.</returns>
+        public virtual int UpdateOrInsert(Type t, IEnumerable e)
         {
             int affected = 0;
-            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(typeof(T));
+            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(t);
 
             if (mapper != null)
             {
@@ -2038,7 +2065,7 @@ namespace DynamORM
                             }
                         }
                         else
-                            PrepareBatchUpdate<T>(mapper, cmdUp, parametersUp);
+                            PrepareBatchUpdate(t, mapper, cmdUp, parametersUp);
 
                         #endregion Update
 
@@ -2063,11 +2090,11 @@ namespace DynamORM
                             }
                         }
                         else
-                            PrepareBatchInsert<T>(mapper, cmdIn, parametersIn);
+                            PrepareBatchInsert(t, mapper, cmdIn, parametersIn);
 
                         #endregion Insert
 
-                        foreach (T o in e)
+                        foreach (var o in e)
                         {
                             foreach (KeyValuePair<IDbDataParameter, DynamicPropertyInvoker> m in parametersUp)
                                 m.Key.Value = m.Value.Get(o);
@@ -2141,9 +2168,18 @@ namespace DynamORM
         /// <param name="e">Enumerable containing instances of objects to delete.</param>
         /// <returns>Number of deleted rows.</returns>
         public virtual int Delete<T>(IEnumerable<T> e) where T : class
+        {
+            return Delete(typeof(T), e);
+        }
+
+        /// <summary>Bulk delete objects in database.</summary>
+        /// <param name="t">Type of objects to delete.</param>
+        /// <param name="e">Enumerable containing instances of objects to delete.</param>
+        /// <returns>Number of deleted rows.</returns>
+        public virtual int Delete(Type t, IEnumerable e)
         {
             int affected = 0;
-            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(typeof(T));
+            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(t);
 
             if (mapper != null)
             {
@@ -2172,9 +2208,9 @@ namespace DynamORM
                             }
                         }
                         else
-                            PrepareBatchDelete<T>(mapper, cmd, parameters);
+                            PrepareBatchDelete(t, mapper, cmd, parameters);
 
-                        foreach (T o in e)
+                        foreach (var o in e)
                         {
                             foreach (KeyValuePair<IDbDataParameter, DynamicPropertyInvoker> m in parameters)
                                 m.Key.Value = m.Value.Get(o);
@@ -2203,13 +2239,18 @@ namespace DynamORM
         }
 
         private void PrepareBatchInsert<T>(DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
+        {
+            PrepareBatchInsert(typeof(T), mapper, cmd, parameters);
+        }
+
+        private void PrepareBatchInsert(Type t, DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
         {
             DynamicPropertyInvoker currentprop = null;
             Dictionary<string, DynamicPropertyInvoker> temp = new Dictionary<string, DynamicPropertyInvoker>();
-            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema<T>();
+            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema(t);
             int ord = 0;
 
-            IDynamicInsertQueryBuilder ib = Insert<T>()
+            IDynamicInsertQueryBuilder ib = Insert(t)
                 .SetVirtualMode(true)
                 .CreateTemporaryParameterAction(p => temp[p.Name] = currentprop)
                 .CreateParameterAction((p, cp) =>
@@ -2250,13 +2291,18 @@ namespace DynamORM
         }
 
         private void PrepareBatchUpdate<T>(DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
+        {
+            PrepareBatchUpdate(typeof(T), mapper, cmd, parameters);
+        }
+
+        private void PrepareBatchUpdate(Type t, DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
         {
             DynamicPropertyInvoker currentprop = null;
             Dictionary<string, DynamicPropertyInvoker> temp = new Dictionary<string, DynamicPropertyInvoker>();
-            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema<T>();
+            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema(t);
             int ord = 0;
 
-            IDynamicUpdateQueryBuilder ib = Update<T>()
+            IDynamicUpdateQueryBuilder ib = Update(t)
                 .SetVirtualMode(true)
                 .CreateTemporaryParameterAction(p => temp[p.Name] = currentprop)
                 .CreateParameterAction((p, cp) =>
@@ -2323,13 +2369,18 @@ namespace DynamORM
         }
 
         private void PrepareBatchDelete<T>(DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
+        {
+            PrepareBatchDelete(typeof(T), mapper, cmd, parameters);
+        }
+
+        private void PrepareBatchDelete(Type t, DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
         {
             DynamicPropertyInvoker currentprop = null;
             Dictionary<string, DynamicPropertyInvoker> temp = new Dictionary<string, DynamicPropertyInvoker>();
-            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema<T>();
+            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema(t);
             int ord = 0;
 
-            IDynamicDeleteQueryBuilder ib = Delete<T>()
+            IDynamicDeleteQueryBuilder ib = Delete(t)
                 .SetVirtualMode(true)
                 .CreateTemporaryParameterAction(p => temp[p.Name] = currentprop)
                 .CreateParameterAction((p, cp) =>
@@ -4791,7 +4842,7 @@ namespace DynamORM
         {
             Type generic = type.IsGenericType ? type.GetGenericTypeDefinition() : null;
 
-            if (generic != null && generic.Equals(typeof(Nullable<>)) && type.IsClass)
+            if (generic != null && generic.Equals(typeof(Nullable<>)) && (type.IsClass || type.IsValueType || type.IsEnum))
                 return true;
 
             return false;
@@ -13322,6 +13373,9 @@ namespace DynamORM
 
                 Column = attr;
 
+                if (attr != null && attr.AllowNull && Type.IsNullableType())
+                    attr.AllowNull = false;
+
                 if (property.CanRead)
                     Get = CreateGetter(property);
 
diff --git a/DynamORM/DynamicDatabase.cs b/DynamORM/DynamicDatabase.cs
index faf8ff8..7d5bade 100644
--- a/DynamORM/DynamicDatabase.cs
+++ b/DynamORM/DynamicDatabase.cs
@@ -27,6 +27,7 @@
 */
 
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
@@ -379,9 +380,18 @@ namespace DynamORM
         /// <param name="e">Enumerable containing instances of objects to insert.</param>
         /// <returns>Number of inserted rows.</returns>
         public virtual int Insert<T>(IEnumerable<T> e) where T : class
+        {
+            return Insert(typeof(T), e);
+        }
+
+        /// <summary>Bulk insert objects into database.</summary>
+        /// <param name="t">Type of objects to insert.</param>
+        /// <param name="e">Enumerable containing instances of objects to insert.</param>
+        /// <returns>Number of inserted rows.</returns>
+        public virtual int Insert(Type t, IEnumerable e)
         {
             int affected = 0;
-            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(typeof(T));
+            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(t);
 
             if (mapper != null)
             {
@@ -410,9 +420,9 @@ namespace DynamORM
                             }
                         }
                         else
-                            PrepareBatchInsert<T>(mapper, cmd, parameters);
+                            PrepareBatchInsert(t, mapper, cmd, parameters);
 
-                        foreach (T o in e)
+                        foreach (var o in e)
                         {
                             foreach (KeyValuePair<IDbDataParameter, DynamicPropertyInvoker> m in parameters)
                                 m.Key.Value = m.Value.Get(o);
@@ -477,9 +487,18 @@ namespace DynamORM
         /// <param name="e">Enumerable containing instances of objects to update.</param>
         /// <returns>Number of updated rows.</returns>
         public virtual int Update<T>(IEnumerable<T> e) where T : class
+        {
+            return Update(typeof(T), e);
+        }
+
+        /// <summary>Bulk update objects in database.</summary>
+        /// <param name="T">Type of objects to update.</param>
+        /// <param name="e">Enumerable containing instances of objects to update.</param>
+        /// <returns>Number of updated rows.</returns>
+        public virtual int Update(Type t, IEnumerable e)
         {
             int affected = 0;
-            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(typeof(T));
+            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(t);
 
             if (mapper != null)
             {
@@ -508,9 +527,9 @@ namespace DynamORM
                             }
                         }
                         else
-                            PrepareBatchUpdate<T>(mapper, cmd, parameters);
+                            PrepareBatchUpdate(t, mapper, cmd, parameters);
 
-                        foreach (T o in e)
+                        foreach (var o in e)
                         {
                             foreach (KeyValuePair<IDbDataParameter, DynamicPropertyInvoker> m in parameters)
                                 m.Key.Value = m.Value.Get(o);
@@ -543,9 +562,18 @@ namespace DynamORM
         /// <param name="e">Enumerable containing instances of objects to update or insert.</param>
         /// <returns>Number of updated or inserted rows.</returns>
         public virtual int UpdateOrInsert<T>(IEnumerable<T> e) where T : class
+        {
+            return UpdateOrInsert(typeof(T), e);
+        }
+
+        /// <summary>Bulk update or insert objects into database.</summary>
+        /// <param name="t">Type of objects to update or insert.</param>
+        /// <param name="e">Enumerable containing instances of objects to update or insert.</param>
+        /// <returns>Number of updated or inserted rows.</returns>
+        public virtual int UpdateOrInsert(Type t, IEnumerable e)
         {
             int affected = 0;
-            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(typeof(T));
+            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(t);
 
             if (mapper != null)
             {
@@ -577,7 +605,7 @@ namespace DynamORM
                             }
                         }
                         else
-                            PrepareBatchUpdate<T>(mapper, cmdUp, parametersUp);
+                            PrepareBatchUpdate(t, mapper, cmdUp, parametersUp);
 
                         #endregion Update
 
@@ -602,11 +630,11 @@ namespace DynamORM
                             }
                         }
                         else
-                            PrepareBatchInsert<T>(mapper, cmdIn, parametersIn);
+                            PrepareBatchInsert(t, mapper, cmdIn, parametersIn);
 
                         #endregion Insert
 
-                        foreach (T o in e)
+                        foreach (var o in e)
                         {
                             foreach (KeyValuePair<IDbDataParameter, DynamicPropertyInvoker> m in parametersUp)
                                 m.Key.Value = m.Value.Get(o);
@@ -680,9 +708,18 @@ namespace DynamORM
         /// <param name="e">Enumerable containing instances of objects to delete.</param>
         /// <returns>Number of deleted rows.</returns>
         public virtual int Delete<T>(IEnumerable<T> e) where T : class
+        {
+            return Delete(typeof(T), e);
+        }
+
+        /// <summary>Bulk delete objects in database.</summary>
+        /// <param name="t">Type of objects to delete.</param>
+        /// <param name="e">Enumerable containing instances of objects to delete.</param>
+        /// <returns>Number of deleted rows.</returns>
+        public virtual int Delete(Type t, IEnumerable e)
         {
             int affected = 0;
-            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(typeof(T));
+            DynamicTypeMap mapper = DynamicMapperCache.GetMapper(t);
 
             if (mapper != null)
             {
@@ -711,9 +748,9 @@ namespace DynamORM
                             }
                         }
                         else
-                            PrepareBatchDelete<T>(mapper, cmd, parameters);
+                            PrepareBatchDelete(t, mapper, cmd, parameters);
 
-                        foreach (T o in e)
+                        foreach (var o in e)
                         {
                             foreach (KeyValuePair<IDbDataParameter, DynamicPropertyInvoker> m in parameters)
                                 m.Key.Value = m.Value.Get(o);
@@ -742,13 +779,18 @@ namespace DynamORM
         }
 
         private void PrepareBatchInsert<T>(DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
+        {
+            PrepareBatchInsert(typeof(T), mapper, cmd, parameters);
+        }
+
+        private void PrepareBatchInsert(Type t, DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
         {
             DynamicPropertyInvoker currentprop = null;
             Dictionary<string, DynamicPropertyInvoker> temp = new Dictionary<string, DynamicPropertyInvoker>();
-            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema<T>();
+            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema(t);
             int ord = 0;
 
-            IDynamicInsertQueryBuilder ib = Insert<T>()
+            IDynamicInsertQueryBuilder ib = Insert(t)
                 .SetVirtualMode(true)
                 .CreateTemporaryParameterAction(p => temp[p.Name] = currentprop)
                 .CreateParameterAction((p, cp) =>
@@ -789,13 +831,18 @@ namespace DynamORM
         }
 
         private void PrepareBatchUpdate<T>(DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
+        {
+            PrepareBatchUpdate(typeof(T), mapper, cmd, parameters);
+        }
+
+        private void PrepareBatchUpdate(Type t, DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
         {
             DynamicPropertyInvoker currentprop = null;
             Dictionary<string, DynamicPropertyInvoker> temp = new Dictionary<string, DynamicPropertyInvoker>();
-            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema<T>();
+            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema(t);
             int ord = 0;
 
-            IDynamicUpdateQueryBuilder ib = Update<T>()
+            IDynamicUpdateQueryBuilder ib = Update(t)
                 .SetVirtualMode(true)
                 .CreateTemporaryParameterAction(p => temp[p.Name] = currentprop)
                 .CreateParameterAction((p, cp) =>
@@ -862,13 +909,18 @@ namespace DynamORM
         }
 
         private void PrepareBatchDelete<T>(DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
+        {
+            PrepareBatchDelete(typeof(T), mapper, cmd, parameters);
+        }
+
+        private void PrepareBatchDelete(Type t, DynamicTypeMap mapper, IDbCommand cmd, Dictionary<IDbDataParameter, DynamicPropertyInvoker> parameters)
         {
             DynamicPropertyInvoker currentprop = null;
             Dictionary<string, DynamicPropertyInvoker> temp = new Dictionary<string, DynamicPropertyInvoker>();
-            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema<T>();
+            Dictionary<string, DynamicSchemaColumn> schema = this.GetSchema(t);
             int ord = 0;
 
-            IDynamicDeleteQueryBuilder ib = Delete<T>()
+            IDynamicDeleteQueryBuilder ib = Delete(t)
                 .SetVirtualMode(true)
                 .CreateTemporaryParameterAction(p => temp[p.Name] = currentprop)
                 .CreateParameterAction((p, cp) =>
diff --git a/DynamORM/DynamicExtensions.cs b/DynamORM/DynamicExtensions.cs
index 38f4637..edd9bb5 100644
--- a/DynamORM/DynamicExtensions.cs
+++ b/DynamORM/DynamicExtensions.cs
@@ -1322,7 +1322,7 @@ namespace DynamORM
         {
             Type generic = type.IsGenericType ? type.GetGenericTypeDefinition() : null;
 
-            if (generic != null && generic.Equals(typeof(Nullable<>)) && type.IsClass)
+            if (generic != null && generic.Equals(typeof(Nullable<>)) && (type.IsClass || type.IsValueType || type.IsEnum))
                 return true;
 
             return false;
diff --git a/DynamORM/Mapper/DynamicPropertyInvoker.cs b/DynamORM/Mapper/DynamicPropertyInvoker.cs
index 6e84334..e33b749 100644
--- a/DynamORM/Mapper/DynamicPropertyInvoker.cs
+++ b/DynamORM/Mapper/DynamicPropertyInvoker.cs
@@ -111,6 +111,9 @@ namespace DynamORM.Mapper
 
             Column = attr;
 
+            if (attr != null && attr.AllowNull && Type.IsNullableType())
+                attr.AllowNull = false;
+
             if (property.CanRead)
                 Get = CreateGetter(property);