diff --git a/include/sqlpp11/boolean.h b/include/sqlpp11/boolean.h
index be7b195d..1ae482ac 100644
--- a/include/sqlpp11/boolean.h
+++ b/include/sqlpp11/boolean.h
@@ -162,7 +162,7 @@ namespace sqlpp
 						return _is_null; 
 					}
 
-					bool is_trivial() const
+					bool _is_trivial() const
 					{
 						if (not _is_valid)
 							throw exception("accessing is_null in non-existing row");
diff --git a/include/sqlpp11/floating_point.h b/include/sqlpp11/floating_point.h
index 37c69207..0feb7f7e 100644
--- a/include/sqlpp11/floating_point.h
+++ b/include/sqlpp11/floating_point.h
@@ -161,7 +161,7 @@ namespace sqlpp
 						return _is_null; 
 					}
 
-					bool is_trivial() const
+					bool _is_trivial() const
 					{
 						if (not _is_valid)
 							throw exception("accessing is_null in non-existing row");
diff --git a/include/sqlpp11/integral.h b/include/sqlpp11/integral.h
index c1441fd3..f100e81b 100644
--- a/include/sqlpp11/integral.h
+++ b/include/sqlpp11/integral.h
@@ -162,7 +162,7 @@ namespace sqlpp
 						return _is_null; 
 					}
 
-					bool is_trivial() const
+					bool _is_trivial() const
 					{
 						if (not _is_valid)
 							throw exception("accessing is_null in non-existing row");
diff --git a/include/sqlpp11/rhs_is_trivial.h b/include/sqlpp11/rhs_is_trivial.h
index 14de2675..5a38db17 100644
--- a/include/sqlpp11/rhs_is_trivial.h
+++ b/include/sqlpp11/rhs_is_trivial.h
@@ -63,7 +63,21 @@ namespace sqlpp
 		{
 			static bool _(const T& t)
 			{
-				return t.is_trivial();
+				if (null_is_trivial_value_t<T>::value)
+				{
+					return t._is_trivial();
+				}
+				else
+				{
+					if (t.is_null())
+					{
+						return false;
+					}
+					else
+					{
+						return t._is_trivial();
+					}
+				}
 			}
 		};
 
diff --git a/include/sqlpp11/text.h b/include/sqlpp11/text.h
index d45544f3..d1ba51e2 100644
--- a/include/sqlpp11/text.h
+++ b/include/sqlpp11/text.h
@@ -164,7 +164,7 @@ namespace sqlpp
 						return _value_ptr == nullptr; 
 					}
 
-					bool is_trivial() const
+					bool _is_trivial() const
 					{
 						if (not _is_valid)
 							throw exception("accessing is_null in non-existing row");
diff --git a/include/sqlpp11/tvin.h b/include/sqlpp11/tvin.h
index 7f3cce23..0c541972 100644
--- a/include/sqlpp11/tvin.h
+++ b/include/sqlpp11/tvin.h
@@ -155,8 +155,7 @@ namespace sqlpp
 		auto tvin(Operand operand) -> tvin_arg_t<typename wrap_operand<Operand>::type>
 		{
 			using _operand_t = typename wrap_operand<Operand>::type;
-			static_assert(std::is_same<_operand_t, text_operand>::value
-					or not std::is_same<_operand_t, Operand>::value, "tvin() used with invalid type (only string and primitive types allowed)");
+			static_assert(not std::is_same<_operand_t, Operand>::value or is_result_field_t<Operand>::value, "tvin() used with invalid type (only string and primitive types allowed)");
 			return {{operand}};
 		}
 
diff --git a/include/sqlpp11/wrap_operand.h b/include/sqlpp11/wrap_operand.h
index 0b0f8d23..b6926055 100644
--- a/include/sqlpp11/wrap_operand.h
+++ b/include/sqlpp11/wrap_operand.h
@@ -219,7 +219,7 @@ namespace sqlpp
 		};
 
 	template<typename T>
-		struct wrap_operand<T, typename std::enable_if<std::is_convertible<T, std::string>::value>::type>
+		struct wrap_operand<T, typename std::enable_if<std::is_convertible<T, std::string>::value and not is_result_field_t<T>::value>::type>
 		{
 			using type = text_operand;
 		};