diff --git a/include/sqlpp11/insert.h b/include/sqlpp11/insert.h
index 7947f546..8f0a5eda 100644
--- a/include/sqlpp11/insert.h
+++ b/include/sqlpp11/insert.h
@@ -114,13 +114,9 @@ namespace sqlpp
 					return *this;
 				}
 
-			template<typename Column>
-			//using _insert_value_t = vendor::insert_value_t<typename vendor::wrap_operand<typename Column::_value_type::_cpp_value_type>::type>;
-			using _insert_value_t = vendor::insert_value_t<typename Column::_value_type::_cpp_value_type>;
-
 			template<typename... Column>
 				auto columns(Column... columns)
-				-> set_column_value_list_t<vendor::column_list_t<Column...>, vendor::insert_value_list_t<_insert_value_t<Column>...>>
+				-> set_column_value_list_t<vendor::column_list_t<Column...>, vendor::insert_value_list_t<vendor::insert_value_t<Column>...>>
 				{
 					static_assert(vendor::is_noop<ColumnList>::value, "cannot call columns() twice");
 					static_assert(vendor::is_noop<InsertList>::value, "cannot call columns() after set() or dynamic_set()");
@@ -130,7 +126,7 @@ namespace sqlpp
 						_table,
 						_insert_list,
 						{std::tuple<Column...>{columns...}},
-						vendor::insert_value_list_t<_insert_value_t<Column>...>{},
+						vendor::insert_value_list_t<vendor::insert_value_t<Column>...>{},
 					};
 				}
 
diff --git a/include/sqlpp11/tvin.h b/include/sqlpp11/tvin.h
index c161008d..9e47969c 100644
--- a/include/sqlpp11/tvin.h
+++ b/include/sqlpp11/tvin.h
@@ -38,7 +38,7 @@ namespace sqlpp
 		struct tvin_t
 		{
 			using _operand_t = typename vendor::wrap_operand<T>::type;
-			static_assert(not std::is_same<_operand_t, T>::value, "tvin() used with invalid type (only string and primitive types allowed)");
+			static_assert(std::is_same<_operand_t, vendor::text_operand>::value or not std::is_same<_operand_t, T>::value, "tvin() used with invalid type (only string and primitive types allowed)");
 			using _value_type = typename _operand_t::_value_type;
 
 			tvin_t(T t): 
diff --git a/include/sqlpp11/vendor/insert_value.h b/include/sqlpp11/vendor/insert_value.h
index 9c6fdf33..13835709 100644
--- a/include/sqlpp11/vendor/insert_value.h
+++ b/include/sqlpp11/vendor/insert_value.h
@@ -37,31 +37,51 @@ namespace sqlpp
 {
 	namespace vendor
 	{
-		template<typename ValueType>
+		namespace detail
+		{
+			template<typename Type, bool>
+				struct type_if
+				{
+					using type = Type;
+				};
+
+			template<typename Type>
+				struct type_if<Type, false>
+				{
+					struct type
+					{
+					};
+				};
+		}
+
+		template<typename Column>
 			struct insert_value_t
 			{
 				using _is_insert_value = std::true_type;
-				using _value_t = ValueType;
+				using _pure_value_t = typename Column::_value_type::_cpp_value_type;
+				using _wrapped_value_t = typename wrap_operand<_pure_value_t>::type;
+				using _tvin_t = typename detail::type_if<tvin_t<_pure_value_t>, can_be_null_t<Column>::value>::type; // static asserts and SFINAE do not work together
+				using _null_t = typename detail::type_if<null_t, can_be_null_t<Column>::value>::type; // static asserts and SFINAE do not work together
 
-				insert_value_t(_value_t value):
+				insert_value_t(assignment_t<Column, _wrapped_value_t> assignment):
 					_is_null(false),
 					_is_default(false),
-					_value({value})
+					_value(assignment._rhs)
 				{}
 
-				insert_value_t(tvin_t<_value_t> tvin):
-					_is_null(tvin._is_trivial()),
+				insert_value_t(assignment_t<Column, _tvin_t> assignment):
+					_is_null(assignment._rhs._is_trivial()),
 					_is_default(false),
-					_value({tvin._value})
+					_value(assignment._rhs._value)
 				{}
 
-				insert_value_t(const ::sqlpp::null_t&):
+				insert_value_t(const assignment_t<Column, _null_t>&):
 					_is_null(true),
 					_is_default(false),
 					_value()
 				{}
 
-				insert_value_t(const ::sqlpp::default_value_t&):
+				insert_value_t(const assignment_t<Column, ::sqlpp::default_value_t>&):
 					_is_null(false),
 					_is_default(true),
 					_value()
@@ -75,7 +95,7 @@ namespace sqlpp
 
 				bool _is_null;
 				bool _is_default;
-				typename wrap_operand<_value_t>::type _value;
+				_wrapped_value_t _value;
 			};
 
 		template<typename Context, typename ValueType>
diff --git a/include/sqlpp11/vendor/select_flag_list.h b/include/sqlpp11/vendor/select_flag_list.h
index c58d3f39..ab5e4918 100644
--- a/include/sqlpp11/vendor/select_flag_list.h
+++ b/include/sqlpp11/vendor/select_flag_list.h
@@ -41,7 +41,7 @@ namespace sqlpp
 		template<typename Database, typename T>
 			struct select_flag_list_t
 			{
-				static_assert(detail::wrong<T>::value, "invalid argument for select_flag_list");
+				static_assert(::sqlpp::detail::wrong<T>::value, "invalid argument for select_flag_list");
 			};
 
 		// select_flag_list_t
@@ -54,10 +54,10 @@ namespace sqlpp
 				using size = std::tuple_size<_parameter_tuple_t>;
 
 				// check for duplicate order expressions
-				static_assert(not detail::has_duplicates<Flag...>::value, "at least one duplicate argument detected in select flag list");
+				static_assert(not ::sqlpp::detail::has_duplicates<Flag...>::value, "at least one duplicate argument detected in select flag list");
 
 				// check for invalid order expressions
-				using _valid_flags = typename detail::make_set_if<is_select_flag_t, Flag...>::type;
+				using _valid_flags = typename ::sqlpp::detail::make_set_if<is_select_flag_t, Flag...>::type;
 				static_assert(_valid_flags::size::value == sizeof...(Flag), "at least one argument is not a select flag in select flag list");
 
 				template<typename E>
diff --git a/tests/InterpretTest.cpp b/tests/InterpretTest.cpp
index a58e7328..77670dd8 100644
--- a/tests/InterpretTest.cpp
+++ b/tests/InterpretTest.cpp
@@ -44,10 +44,16 @@ int main()
 	TabFoo f;
 
 	interpret(insert_into(t).columns(t.gamma, t.beta), printer).flush();
-	interpret(insert_into(t).columns(t.gamma, t.beta).add_values(true, "cheesecake"), printer).flush();
-	interpret(insert_into(t).columns(t.gamma, t.beta).add_values(true, "cheesecake").add_values(false, sqlpp::tvin(std::string("coffee"))).add_values(false, sqlpp::tvin(std::string())), printer).flush();
-	interpret(insert_into(t).columns(t.gamma, t.beta).add_values(sqlpp::default_value, sqlpp::null), printer).flush();
-	interpret(insert_into(t).columns(t.gamma, t.beta), printer).flush();
+	interpret(insert_into(t).columns(t.gamma, t.beta).add_values(t.gamma = true, t.beta = "cheesecake"), printer).flush();
+	interpret(insert_into(t).columns(t.gamma, t.beta)
+			.add_values(t.gamma = true, t.beta = "cheesecake")
+			.add_values(t.gamma = false, t.beta = sqlpp::tvin(std::string("coffee"))) // FIXME: Want to use const char* const here, too
+			.add_values(t.gamma = false, t.beta = sqlpp::tvin(std::string()))
+			, printer).flush();
+	interpret(insert_into(t).columns(t.gamma, t.beta)
+			.add_values(t.gamma = sqlpp::default_value, t.beta = sqlpp::null)
+			, printer).flush();
+
 	interpret(t.alpha = sqlpp::null, printer).flush();
 	interpret(t.alpha = sqlpp::default_value, printer).flush();
 	interpret(t.alpha, printer).flush();