Adjusted remaining select parts

include/sqlpp11/select.h

@@ -203,13 +203,13 @@ namespace sqlpp
 			vendor::no_select_flag_list_t, 
 			vendor::no_select_column_list_t, 
 			vendor::no_from_t,
-			//vendor::no_extra_tables_t,
+			vendor::no_extra_tables_t,
-			vendor::no_where_t/*, 
+			vendor::no_where_t, 
 			vendor::no_group_by_t, 
 			vendor::no_having_t,
 			vendor::no_order_by_t, 
 			vendor::no_limit_t, 
-			vendor::no_offset_t*/>;
+			vendor::no_offset_t>;
 
 
 	blank_select_t<void> select() // FIXME: These should be constexpr

include/sqlpp11/vendor/extra_tables.h

@@ -84,9 +84,17 @@ namespace sqlpp
 				template<typename Policies>
 					struct _member_t
 					{
+						using _data_t = extra_tables_data_t<Tables...>;
+
 						_impl_t<Policies> extra_tables;
 						_impl_t<Policies>& operator()() { return extra_tables; }
 						const _impl_t<Policies>& operator()() const { return extra_tables; }
+
+						template<typename T>
+							static auto _get_member(T t) -> decltype(t.extra_tables)
+							{
+								return t.extra_tables;
+							}
 					};
 
 				// Additional methods for the statement
@@ -103,9 +111,7 @@ namespace sqlpp
 			using _recursive_traits = make_recursive_traits<>;
 
 			// Data
-			struct _data_t
+			using _data_t = no_data_t;
-			{
-			};
 
 			// Member implementation with data and methods
 			template<typename Policies>
@@ -118,9 +124,17 @@ namespace sqlpp
 			template<typename Policies>
 				struct _member_t
 				{
-					_impl_t<Policies> no_extra_tables_t;
+					using _data_t = no_data_t;
-					_impl_t<Policies>& operator()() { return no_extra_tables_t; }
+
-					const _impl_t<Policies>& operator()() const { return no_extra_tables_t; }
+					_impl_t<Policies> no_extra_tables;
+					_impl_t<Policies>& operator()() { return no_extra_tables; }
+					const _impl_t<Policies>& operator()() const { return no_extra_tables; }
+
+					template<typename T>
+						static auto _get_member(T t) -> decltype(t.no_extra_tables)
+						{
+							return t.no_extra_tables;
+						}
 				};
 
 			template<typename Policies>
@@ -150,17 +164,6 @@ namespace sqlpp
 				}
 			};
 
-		template<typename Context>
-			struct serializer_t<Context, typename no_extra_tables_t::_data_t>
-			{
-				using T = typename no_extra_tables_t::_data_t;
-
-				static Context& _(const T& t, Context& context)
-				{
-					return context;
-				}
-			};
-
 	}
 }
 

include/sqlpp11/vendor/group_by.h

@@ -39,6 +39,24 @@ namespace sqlpp
 {
 	namespace vendor
 	{
+		// GROUP BY DATA
+		template<typename Database, typename... Expressions>
+			struct group_by_data_t
+			{
+				group_by_data_t(Expressions... expressions):
+					_expressions(expressions...)
+				{}
+
+				group_by_data_t(const group_by_data_t&) = default;
+				group_by_data_t(group_by_data_t&&) = default;
+				group_by_data_t& operator=(const group_by_data_t&) = default;
+				group_by_data_t& operator=(group_by_data_t&&) = default;
+				~group_by_data_t() = default;
+
+				std::tuple<Expressions...> _expressions;
+				vendor::interpretable_list_t<Database> _dynamic_expressions;
+			};
+
 		// GROUP BY
 		template<typename Database, typename... Expressions>
 			struct group_by_t
@@ -54,60 +72,100 @@ namespace sqlpp
 
 				static_assert(::sqlpp::detail::all_t<is_expression_t<Expressions>::value...>::value, "at least one argument is not an expression in group_by()");
 
-				group_by_t& _group_by() { return *this; }
+				// Data
-
+				using _data_t = select_flag_list_data_t<Database, Expressions...>;
-				group_by_t(Expressions... expressions):
-					_expressions(expressions...)
-				{}
-
-				group_by_t(const group_by_t&) = default;
-				group_by_t(group_by_t&&) = default;
-				group_by_t& operator=(const group_by_t&) = default;
-				group_by_t& operator=(group_by_t&&) = default;
-				~group_by_t() = default;
 
+				// Member implementation with data and methods
 				template<typename Policies>
-					struct _methods_t
+					struct _impl_t
 					{
 						template<typename Expression>
-							void add_group_by_ntc(Expression expression)
+							void add_ntc(Expression expression)
 							{
-								add_group_by<Expression, std::false_type>(expression);
+								add<Expression, std::false_type>(expression);
 							}
 
 						template<typename Expression, typename TableCheckRequired = std::true_type>
-							void add_group_by(Expression expression)
+							void add(Expression expression)
 							{
-								static_assert(_is_dynamic::value, "add_group_by must not be called for static group_by");
+								static_assert(_is_dynamic::value, "add() must not be called for static group_by");
-								static_assert(is_expression_t<Expression>::value, "invalid expression argument in add_group_by()");
+								static_assert(is_expression_t<Expression>::value, "invalid expression argument in group_by::add()");
-								static_assert(TableCheckRequired::value or Policies::template _no_unknown_tables<Expression>::value, "expression uses tables unknown to this statement in add_group_by()");
+								static_assert(TableCheckRequired::value or Policies::template _no_unknown_tables<Expression>::value, "expression uses tables unknown to this statement in group_by::add()");
 
 								using ok = ::sqlpp::detail::all_t<_is_dynamic::value, is_expression_t<Expression>::value>;
 
-								_add_group_by_impl(expression, ok()); // dispatch to prevent compile messages after the static_assert
+								_add_impl(expression, ok()); // dispatch to prevent compile messages after the static_assert
 							}
 
 					private:
 						template<typename Expression>
-							void _add_group_by_impl(Expression expression, const std::true_type&)
+							void _add_impl(Expression expression, const std::true_type&)
 							{
-								return static_cast<typename Policies::_statement_t*>(this)->_group_by()._dynamic_expressions.emplace_back(expression);
+								return _data._dynamic_expressions.emplace_back(expression);
 							}
 
 						template<typename Expression>
-							void _add_group_by_impl(Expression expression, const std::false_type&);
+							void _add_impl(Expression expression, const std::false_type&);
+					public:
+						_data_t _data;
 					};
 
-				const group_by_t& _group_by() const { return *this; }
+				// Member template for adding the named member to a statement
-				std::tuple<Expressions...> _expressions;
+				template<typename Policies>
-				vendor::interpretable_list_t<Database> _dynamic_expressions;
+					struct _member_t
+					{
+						using _data_t = group_by_data_t<Database, Expressions...>;
+
+						_impl_t<Policies> group_by;
+						_impl_t<Policies>& operator()() { return group_by; }
+						const _impl_t<Policies>& operator()() const { return group_by; }
+
+						template<typename T>
+							static auto _get_member(T t) -> decltype(t.group_by)
+							{
+								return t.group_by;
+							}
 					};
 
+				template<typename Policies>
+					struct _methods_t
+					{
+					};
+			};
+
+		// NO GROUP BY YET
 		struct no_group_by_t
 		{
 			using _traits = make_traits<no_value_t, ::sqlpp::tag::noop>;
 			using _recursive_traits = make_recursive_traits<>;
 
+			// Data
+			using _data_t = no_data_t;
+
+			// Member implementation with data and methods
+			template<typename Policies>
+				struct _impl_t
+				{
+					_data_t _data;
+				};
+
+			// Member template for adding the named member to a statement
+			template<typename Policies>
+				struct _member_t
+				{
+					using _data_t = no_data_t;
+
+					_impl_t<Policies> no_group_by;
+					_impl_t<Policies>& operator()() { return no_group_by; }
+					const _impl_t<Policies>& operator()() const { return no_group_by; }
+
+					template<typename T>
+						static auto _get_member(T t) -> decltype(t.no_group_by)
+						{
+							return t.no_group_by;
+						}
+				};
+
 			template<typename Policies>
 				struct _methods_t
 				{
@@ -119,7 +177,7 @@ namespace sqlpp
 						auto group_by(Args... args)
 						-> _new_statement_t<group_by_t<void, Args...>>
 						{
-							return { *static_cast<typename Policies::_statement_t*>(this), group_by_t<void, Args...>{args...} };
+							return { *static_cast<typename Policies::_statement_t*>(this), group_by_data_t<void, Args...>{args...} };
 						}
 
 					template<typename... Args>
@@ -127,16 +185,16 @@ namespace sqlpp
 						-> _new_statement_t<group_by_t<_database_t, Args...>>
 						{
 							static_assert(not std::is_same<_database_t, void>::value, "dynamic_group_by must not be called in a static statement");
-							return { *static_cast<typename Policies::_statement_t*>(this), vendor::group_by_t<_database_t, Args...>{args...} };
+							return { *static_cast<typename Policies::_statement_t*>(this), group_by_data_t<_database_t, Args...>{args...} };
 						}
 				};
 		};
 
 		// Interpreters
 		template<typename Context, typename Database, typename... Expressions>
-			struct serializer_t<Context, group_by_t<Database, Expressions...>>
+			struct serializer_t<Context, group_by_data_t<Database, Expressions...>>
 			{
-				using T = group_by_t<Database, Expressions...>;
+				using T = group_by_data_t<Database, Expressions...>;
 
 				static Context& _(const T& t, Context& context)
 				{
@@ -150,18 +208,6 @@ namespace sqlpp
 					return context;
 				}
 			};
-
-		template<typename Context>
-			struct serializer_t<Context, no_group_by_t>
-			{
-				using T = no_group_by_t;
-
-				static Context& _(const T& t, Context& context)
-				{
-					return context;
-				}
-			};
-
 	}
 }
 

include/sqlpp11/vendor/having.h

@@ -38,6 +38,24 @@ namespace sqlpp
 {
 	namespace vendor
 	{
+		// HAVING DATA
+		template<typename Database, typename... Expressions>
+			struct having_data_t
+			{
+				having_data_t(Expressions... expressions):
+					_expressions(expressions...)
+				{}
+
+				having_data_t(const having_data_t&) = default;
+				having_data_t(having_data_t&&) = default;
+				having_data_t& operator=(const having_data_t&) = default;
+				having_data_t& operator=(having_data_t&&) = default;
+				~having_data_t() = default;
+
+				std::tuple<Expressions...> _expressions;
+				vendor::interpretable_list_t<Database> _dynamic_expressions;
+			};
+
 		// HAVING
 		template<typename Database, typename... Expressions>
 			struct having_t
@@ -50,59 +68,102 @@ namespace sqlpp
 				static_assert(_is_dynamic::value or sizeof...(Expressions), "at least one expression argument required in having()");
 				static_assert(::sqlpp::detail::all_t<is_expression_t<Expressions>::value...>::value, "at least one argument is not an expression in having()");
 
-				having_t& _having() { return *this; }
+				// Data
-
+				using _data_t = having_data_t<Database, Expressions...>;
-				having_t(Expressions... expressions):
-					_expressions(expressions...)
-				{}
-
-				having_t(const having_t&) = default;
-				having_t(having_t&&) = default;
-				having_t& operator=(const having_t&) = default;
-				having_t& operator=(having_t&&) = default;
-				~having_t() = default;
 
+				// Member implementation with data and methods
 				template <typename Policies>
-					struct _methods_t
+					struct _impl_t
 					{
 						template<typename Expression>
-							void add_having_ntc(Expression expression)
+							void add_ntc(Expression expression)
 							{
-								add_having<Expression, std::false_type>(expression);
+								add<Expression, std::false_type>(expression);
 							}
 
 						template<typename Expression, typename TableCheckRequired = std::true_type>
-							void add_having(Expression expression)
+							void add(Expression expression)
 							{
-								static_assert(_is_dynamic::value, "add_having must not be called for static having");
+								static_assert(_is_dynamic::value, "having::add() can only be called for dynamic_having");
-								static_assert(is_expression_t<Expression>::value, "invalid expression argument in add_having()");
+								static_assert(is_expression_t<Expression>::value, "invalid expression argument in having::add()");
-								static_assert(TableCheckRequired::value or Policies::template _no_unknown_tables<Expression>::value, "expression uses tables unknown to this statement in add_having()");
+								static_assert(not TableCheckRequired::value or Policies::template _no_unknown_tables<Expression>::value, "expression uses tables unknown to this statement in having::add()");
 
 								using ok = ::sqlpp::detail::all_t<_is_dynamic::value, is_expression_t<Expression>::value>;
 
-								_add_having_impl(expression, ok()); // dispatch to prevent compile messages after the static_assert
+								_add_impl(expression, ok()); // dispatch to prevent compile messages after the static_assert
 							}
 
 					private:
 						template<typename Expression>
-							void _add_having_impl(Expression expression, const std::true_type&)
+							void _add_impl(Expression expression, const std::true_type&)
 							{
-								return static_cast<typename Policies::_statement_t*>(this)->_having()._dynamic_expressions.emplace_back(expression);
+								return _data._dynamic_expressions.emplace_back(expression);
 							}
 
 						template<typename Expression>
-							void _add_having_impl(Expression expression, const std::false_type&);
+							void _add_impl(Expression expression, const std::false_type&);
+
+					public:
+						_data_t _data;
 					};
 
-				std::tuple<Expressions...> _expressions;
+				// Member template for adding the named member to a statement
-				vendor::interpretable_list_t<Database> _dynamic_expressions;
+				template<typename Policies>
+					struct _member_t
+					{
+						using _data_t = having_data_t<Database, Expressions...>;
+
+						_impl_t<Policies> having;
+						_impl_t<Policies>& operator()() { return having; }
+						const _impl_t<Policies>& operator()() const { return having; }
+
+						template<typename T>
+							static auto _get_member(T t) -> decltype(t.having)
+							{
+								return t.having;
+							}
 					};
 
+				// Additional methods for the statement
+				template<typename Policies>
+					struct _methods_t
+					{
+					};
+			};
+
+		// NO HAVING YET
 		struct no_having_t
 		{
 			using _traits = make_traits<no_value_t, ::sqlpp::tag::noop>;
 			using _recursive_traits = make_recursive_traits<>;
 
+			// Data
+			using _data_t = no_data_t;
+
+			// Member implementation with data and methods
+			template<typename Policies>
+				struct _impl_t
+				{
+					_data_t _data;
+				};
+
+			// Member template for adding the named member to a statement
+			template<typename Policies>
+				struct _member_t
+				{
+					using _data_t = no_data_t;
+
+					_impl_t<Policies> no_having;
+					_impl_t<Policies>& operator()() { return no_having; }
+					const _impl_t<Policies>& operator()() const { return no_having; }
+
+					template<typename T>
+						static auto _get_member(T t) -> decltype(t.no_having)
+						{
+							return t.no_having;
+						}
+				};
+
 			template<typename Policies>
 				struct _methods_t
 				{
@@ -114,7 +175,7 @@ namespace sqlpp
 						auto having(Args... args)
 						-> _new_statement_t<having_t<void, Args...>>
 						{
-							return { *static_cast<typename Policies::_statement_t*>(this), having_t<void, Args...>{args...} };
+							return { *static_cast<typename Policies::_statement_t*>(this), having_data_t<void, Args...>{args...} };
 						}
 
 					template<typename... Args>
@@ -122,16 +183,16 @@ namespace sqlpp
 						-> _new_statement_t<having_t<_database_t, Args...>>
 						{
 							static_assert(not std::is_same<_database_t, void>::value, "dynamic_having must not be called in a static statement");
-							return { *static_cast<typename Policies::_statement_t*>(this), vendor::having_t<_database_t, Args...>{args...} };
+							return { *static_cast<typename Policies::_statement_t*>(this), having_data_t<_database_t, Args...>{args...} };
 						}
 				};
 		};
 
 		// Interpreters
 		template<typename Context, typename Database, typename... Expressions>
-			struct serializer_t<Context, having_t<Database, Expressions...>>
+			struct serializer_t<Context, having_data_t<Database, Expressions...>>
 			{
-				using T = having_t<Database, Expressions...>;
+				using T = having_data_t<Database, Expressions...>;
 
 				static Context& _(const T& t, Context& context)
 				{
@@ -145,18 +206,6 @@ namespace sqlpp
 					return context;
 				}
 			};
-
-		template<typename Context>
-			struct serializer_t<Context, no_having_t>
-			{
-				using T = no_having_t;
-
-				static Context& _(const T& t, Context& context)
-				{
-					return context;
-				}
-			};
-
 	}
 }
 

include/sqlpp11/vendor/limit.h

@@ -35,6 +35,23 @@ namespace sqlpp
 {
 	namespace vendor
 	{
+		// LIMIT DATA
+		template<typename Limit>
+			struct limit_data_t
+			{
+				limit_data_t(Limit value):
+					_value(value)
+				{}
+
+				limit_data_t(const limit_data_t&) = default;
+				limit_data_t(limit_data_t&&) = default;
+				limit_data_t& operator=(const limit_data_t&) = default;
+				limit_data_t& operator=(limit_data_t&&) = default;
+				~limit_data_t() = default;
+
+				Limit _value;
+			};
+
 		// LIMIT
 		template<typename Limit>
 			struct limit_t
@@ -44,65 +61,109 @@ namespace sqlpp
 
 				static_assert(is_integral_t<Limit>::value, "limit requires an integral value or integral parameter");
 
-				limit_t(Limit value):
+				// Data
-					_value(value)
+				using _data_t = limit_data_t<Limit>;
-				{}
 
-				limit_t(const limit_t&) = default;
+				// Member implementation with data and methods
-				limit_t(limit_t&&) = default;
+				template <typename Policies>
-				limit_t& operator=(const limit_t&) = default;
+					struct _impl_t
-				limit_t& operator=(limit_t&&) = default;
+					{
-				~limit_t() = default;
+						_data_t _data;
+					};
+
+				// Member template for adding the named member to a statement
+				template<typename Policies>
+					struct _member_t
+					{
+						_impl_t<Policies> limit;
+						_impl_t<Policies>& operator()() { return limit; }
+						const _impl_t<Policies>& operator()() const { return limit; }
+
+						template<typename T>
+							static auto _get_member(T t) -> decltype(t.limit)
+							{
+								return t.limit;
+							}
+					};
 
 				template<typename Policies>
 					struct _methods_t
 					{
 					};
-
-				Limit _value;
 			};
 
+		// DYNAMIC LIMIT DATA
+		template<typename Database>
+			struct dynamic_limit_data_t
+			{
+				dynamic_limit_data_t():
+					_value(noop())
+				{
+				}
+
+				template<typename Limit>
+					dynamic_limit_data_t(Limit value):
+						_initialized(true),
+						_value(typename wrap_operand<Limit>::type(value))
+				{
+				}
+
+				dynamic_limit_data_t(const dynamic_limit_data_t&) = default;
+				dynamic_limit_data_t(dynamic_limit_data_t&&) = default;
+				dynamic_limit_data_t& operator=(const dynamic_limit_data_t&) = default;
+				dynamic_limit_data_t& operator=(dynamic_limit_data_t&&) = default;
+				~dynamic_limit_data_t() = default;
+
+				bool _initialized = false;
+				interpretable_t<Database> _value;
+			};
+
+		// DYNAMIC LIMIT
 		template<typename Database>
 			struct dynamic_limit_t
 			{
 				using _traits = make_traits<no_value_t, ::sqlpp::tag::limit>;
 				using _recursive_traits = make_recursive_traits<>;
 
-				dynamic_limit_t& _limit() { return *this; }
+				// Data
-
+				using _data_t = limit_data_t<Database>;
-				dynamic_limit_t():
-					_value(noop())
-				{
-				}
-
-				template<typename Limit>
-					dynamic_limit_t(Limit value):
-						_initialized(true),
-						_value(typename wrap_operand<Limit>::type(value))
-				{
-				}
-
-				dynamic_limit_t(const dynamic_limit_t&) = default;
-				dynamic_limit_t(dynamic_limit_t&&) = default;
-				dynamic_limit_t& operator=(const dynamic_limit_t&) = default;
-				dynamic_limit_t& operator=(dynamic_limit_t&&) = default;
-				~dynamic_limit_t() = default;
 
+				// Member implementation with data and methods
 				template <typename Policies>
-					struct _methods_t
+					struct _impl_t
 					{
 						template<typename Limit>
-							void set_limit(Limit value)
+							void set(Limit value)
 							{
 								// FIXME: Make sure that Limit does not require external tables? Need to read up on SQL
 								using arg_t = typename wrap_operand<Limit>::type;
-								static_cast<typename Policies::_statement_t*>(this)->_limit()._value = arg_t{value};
+								_data._value = arg_t{value};
-								static_cast<typename Policies::_statement_t*>(this)->_limit()._initialized = true;
+								_data._initialized = true;
+							}
+					public:
+						_data_t _data;
+					};
+
+				// Member template for adding the named member to a statement
+				template<typename Policies>
+					struct _member_t
+					{
+						_impl_t<Policies> limit;
+						_impl_t<Policies>& operator()() { return limit; }
+						const _impl_t<Policies>& operator()() const { return limit; }
+
+						template<typename T>
+							static auto _get_member(T t) -> decltype(t.limit)
+							{
+								return t.limit;
 							}
 					};
 
-				bool _initialized = false;
+				// Additional methods for the statement
-				interpretable_t<Database> _value;
+				template<typename Policies>
+					struct _methods_t
+					{
+					};
 			};
 
 		struct no_limit_t
@@ -110,6 +171,33 @@ namespace sqlpp
 			using _traits = make_traits<no_value_t, ::sqlpp::tag::noop>;
 			using _recursive_traits = make_recursive_traits<>;
 
+			// Data
+			using _data_t = no_data_t;
+
+			// Member implementation with data and methods
+			template<typename Policies>
+				struct _impl_t
+				{
+					_data_t _data;
+				};
+
+			// Member template for adding the named member to a statement
+			template<typename Policies>
+				struct _member_t
+				{
+					using _data_t = no_data_t;
+
+					_impl_t<Policies> no_limit;
+					_impl_t<Policies>& operator()() { return no_limit; }
+					const _impl_t<Policies>& operator()() const { return no_limit; }
+
+					template<typename T>
+						static auto _get_member(T t) -> decltype(t.no_limit)
+						{
+							return t.no_limit;
+						}
+				};
+
 			template<typename Policies>
 				struct _methods_t
 				{
@@ -121,23 +209,23 @@ namespace sqlpp
 						auto limit(Arg arg)
 						-> _new_statement_t<limit_t<typename wrap_operand<Arg>::type>>
 						{
-							return { *static_cast<typename Policies::_statement_t*>(this), limit_t<typename wrap_operand<Arg>::type>{{arg}} };
+							return { *static_cast<typename Policies::_statement_t*>(this), limit_data_t<typename wrap_operand<Arg>::type>{{arg}} };
 						}
 
 					auto dynamic_limit()
 						-> _new_statement_t<dynamic_limit_t<_database_t>>
 						{
 							static_assert(not std::is_same<_database_t, void>::value, "dynamic_limit must not be called in a static statement");
-							return { *static_cast<typename Policies::_statement_t*>(this), dynamic_limit_t<_database_t>{} };
+							return { *static_cast<typename Policies::_statement_t*>(this), dynamic_limit_data_t<_database_t>{} };
 						}
 				};
 		};
 
 		// Interpreters
 		template<typename Context, typename Database>
-			struct serializer_t<Context, dynamic_limit_t<Database>>
+			struct serializer_t<Context, dynamic_limit_data_t<Database>>
 			{
-				using T = dynamic_limit_t<Database>;
+				using T = dynamic_limit_data_t<Database>;
 
 				static Context& _(const T& t, Context& context)
 				{
@@ -162,18 +250,6 @@ namespace sqlpp
 					return context;
 				}
 			};
-
-		template<typename Context>
-			struct serializer_t<Context, no_limit_t>
-			{
-				using T = no_limit_t;
-
-				static Context& _(const T& t, Context& context)
-				{
-					return context;
-				}
-			};
-
 	}
 }
 

include/sqlpp11/vendor/offset.h

@@ -35,6 +35,23 @@ namespace sqlpp
 {
 	namespace vendor
 	{
+		// OFFSET DATA
+		template<typename Offset>
+			struct offset_data_t
+			{
+				offset_data_t(Offset value):
+					_value(value)
+				{}
+
+				offset_data_t(const offset_data_t&) = default;
+				offset_data_t(offset_data_t&&) = default;
+				offset_data_t& operator=(const offset_data_t&) = default;
+				offset_data_t& operator=(offset_data_t&&) = default;
+				~offset_data_t() = default;
+
+				Offset _value;
+			};
+
 		// OFFSET
 		template<typename Offset>
 			struct offset_t
@@ -44,49 +61,103 @@ namespace sqlpp
 
 				static_assert(is_integral_t<Offset>::value, "offset requires an integral value or integral parameter");
 
-				offset_t(Offset value):
+				// Data
-					_value(value)
+				using _data_t = offset_data_t<Offset>;
-				{}
 
-				offset_t(const offset_t&) = default;
+				// Member implementation with data and methods
-				offset_t(offset_t&&) = default;
+				template <typename Policies>
-				offset_t& operator=(const offset_t&) = default;
+					struct _impl_t
-				offset_t& operator=(offset_t&&) = default;
+					{
-				~offset_t() = default;
+						_data_t _data;
+					};
+
+				// Member template for adding the named member to a statement
+				template<typename Policies>
+					struct _member_t
+					{
+						_impl_t<Policies> offset;
+						_impl_t<Policies>& operator()() { return offset; }
+						const _impl_t<Policies>& operator()() const { return offset; }
+
+						template<typename T>
+							static auto _get_member(T t) -> decltype(t.offset)
+							{
+								return t.offset;
+							}
+					};
 
 				template<typename Policies>
 					struct _methods_t
 					{
 					};
-
-				Offset _value;
 			};
 
+		// DYNAMIC OFFSET DATA
+		template<typename Database>
+			struct dynamic_offset_data_t
+			{
+				dynamic_offset_data_t():
+					_value(noop())
+				{
+				}
+
+				template<typename Offset>
+					dynamic_offset_data_t(Offset value):
+						_initialized(true),
+						_value(typename wrap_operand<Offset>::type(value))
+				{
+				}
+
+				dynamic_offset_data_t(const dynamic_offset_data_t&) = default;
+				dynamic_offset_data_t(dynamic_offset_data_t&&) = default;
+				dynamic_offset_data_t& operator=(const dynamic_offset_data_t&) = default;
+				dynamic_offset_data_t& operator=(dynamic_offset_data_t&&) = default;
+				~dynamic_offset_data_t() = default;
+
+				bool _initialized = false;
+				interpretable_t<Database> _value;
+			};
+
+		// DYNAMIC OFFSET
 		template<typename Database>
 			struct dynamic_offset_t
 			{
 				using _traits = make_traits<no_value_t, ::sqlpp::tag::offset>;
 				using _recursive_traits = make_recursive_traits<>;
 
-				dynamic_offset_t& _offset() { return *this; }
+				// Data
+				using _data_t = offset_data_t<Database>;
 
-				dynamic_offset_t():
+				// Member implementation with data and methods
-					_value(noop())
+				template <typename Policies>
+					struct _impl_t
 					{
-				}
-
 						template<typename Offset>
-					dynamic_offset_t(Offset value):
+							void set(Offset value)
-						_initialized(true),
-						_value(typename wrap_operand<Offset>::type(value))
 							{
+								// FIXME: Make sure that Offset does not require external tables? Need to read up on SQL
+								using arg_t = typename wrap_operand<Offset>::type;
+								_data._value = arg_t{value};
+								_data._initialized = true;
 							}
+					public:
+						_data_t _data;
+					};
 
-				dynamic_offset_t(const dynamic_offset_t&) = default;
+				// Member template for adding the named member to a statement
-				dynamic_offset_t(dynamic_offset_t&&) = default;
+				template<typename Policies>
-				dynamic_offset_t& operator=(const dynamic_offset_t&) = default;
+					struct _member_t
-				dynamic_offset_t& operator=(dynamic_offset_t&&) = default;
+					{
-				~dynamic_offset_t() = default;
+						_impl_t<Policies> offset;
+						_impl_t<Policies>& operator()() { return offset; }
+						const _impl_t<Policies>& operator()() const { return offset; }
+
+						template<typename T>
+							static auto _get_member(T t) -> decltype(t.offset)
+							{
+								return t.offset;
+							}
+					};
 
 				template<typename Policies>
 					struct _methods_t
@@ -110,6 +181,33 @@ namespace sqlpp
 			using _traits = make_traits<no_value_t, ::sqlpp::tag::noop>;
 			using _recursive_traits = make_recursive_traits<>;
 
+			// Data
+			using _data_t = no_data_t;
+
+			// Member implementation with data and methods
+			template<typename Policies>
+				struct _impl_t
+				{
+					_data_t _data;
+				};
+
+			// Member template for adding the named member to a statement
+			template<typename Policies>
+				struct _member_t
+				{
+					using _data_t = no_data_t;
+
+					_impl_t<Policies> no_offset;
+					_impl_t<Policies>& operator()() { return no_offset; }
+					const _impl_t<Policies>& operator()() const { return no_offset; }
+
+					template<typename T>
+						static auto _get_member(T t) -> decltype(t.no_offset)
+						{
+							return t.no_offset;
+						}
+				};
+
 			template<typename Policies>
 				struct _methods_t
 				{
@@ -121,14 +219,14 @@ namespace sqlpp
 						auto offset(Arg arg)
 						-> _new_statement_t<offset_t<typename wrap_operand<Arg>::type>>
 						{
-							return { *static_cast<typename Policies::_statement_t*>(this), offset_t<typename wrap_operand<Arg>::type>{{arg}} };
+							return { *static_cast<typename Policies::_statement_t*>(this), offset_data_t<typename wrap_operand<Arg>::type>{{arg}} };
 						}
 
 					auto dynamic_offset()
 						-> _new_statement_t<dynamic_offset_t<_database_t>>
 						{
 							static_assert(not std::is_same<_database_t, void>::value, "dynamic_offset must not be called in a static statement");
-							return { *static_cast<typename Policies::_statement_t*>(this), dynamic_offset_t<_database_t>{} };
+							return { *static_cast<typename Policies::_statement_t*>(this), dynamic_offset_data_t<_database_t>{} };
 						}
 				};
 		};
@@ -162,17 +260,6 @@ namespace sqlpp
 					return context;
 				}
 			};
-
-		template<typename Context>
-			struct serializer_t<Context, no_offset_t>
-			{
-				using T = no_offset_t;
-
-				static Context& _(const T& t, Context& context)
-				{
-					return context;
-				}
-			};
 	}
 }
 

include/sqlpp11/vendor/order_by.h

@@ -39,73 +39,133 @@ namespace sqlpp
 {
 	namespace vendor
 	{
+		// ORDER BY DATA
 		template<typename Database, typename... Expressions>
-			struct order_by_t
+			struct order_by_data_t
 			{
-				using _traits = make_traits<no_value_t, ::sqlpp::tag::group_by>;
+				order_by_data_t(Expressions... expressions):
-				using _recursive_traits = make_recursive_traits<Expressions...>;
-
-				using _is_dynamic = typename std::conditional<std::is_same<Database, void>::value, std::false_type, std::true_type>::type;
-
-				static_assert(_is_dynamic::value or sizeof...(Expressions), "at least one sort-order expression required in order_by()");
-
-				static_assert(not ::sqlpp::detail::has_duplicates<Expressions...>::value, "at least one duplicate argument detected in order_by()");
-
-				static_assert(::sqlpp::detail::all_t<is_sort_order_t<Expressions>::value...>::value, "at least one argument is not a sort order expression in order_by()");
-
-				order_by_t& _order_by() { return *this; }
-
-				order_by_t(Expressions... expressions):
 					_expressions(expressions...)
 				{}
 
-				order_by_t(const order_by_t&) = default;
+				order_by_data_t(const order_by_data_t&) = default;
-				order_by_t(order_by_t&&) = default;
+				order_by_data_t(order_by_data_t&&) = default;
-				order_by_t& operator=(const order_by_t&) = default;
+				order_by_data_t& operator=(const order_by_data_t&) = default;
-				order_by_t& operator=(order_by_t&&) = default;
+				order_by_data_t& operator=(order_by_data_t&&) = default;
-				~order_by_t() = default;
+				~order_by_data_t() = default;
-
-				template<typename Policies>
-					struct _methods_t
-					{
-						template<typename Expression>
-							void add_order_by_ntc(Expression expression)
-							{
-								add_order_by<Expression, std::false_type>(expression);
-							}
-
-						template<typename Expression, typename TableCheckRequired = std::true_type>
-							void add_order_by(Expression expression)
-							{
-								static_assert(_is_dynamic::value, "add_order_by must not be called for static order_by");
-								static_assert(is_sort_order_t<Expression>::value, "invalid expression argument in add_order_by()");
-								static_assert(TableCheckRequired::value or Policies::template _no_unknown_tables<Expression>::value, "expression uses tables unknown to this statement in add_order_by()");
-
-								using ok = ::sqlpp::detail::all_t<_is_dynamic::value, is_sort_order_t<Expression>::value>;
-
-								_add_order_by_impl(expression, ok()); // dispatch to prevent compile messages after the static_assert
-							}
-
-					private:
-						template<typename Expression>
-							void _add_order_by_impl(Expression expression, const std::true_type&)
-							{
-								return static_cast<typename Policies::_statement_t*>(this)->_order_by()._dynamic_expressions.emplace_back(expression);
-							}
-
-						template<typename Expression>
-							void _add_order_by_impl(Expression expression, const std::false_type&);
-					};
 
 				std::tuple<Expressions...> _expressions;
 				vendor::interpretable_list_t<Database> _dynamic_expressions;
 			};
 
+		// ORDER BY
+		template<typename Database, typename... Expressions>
+			struct order_by_t
+			{
+				using _traits = make_traits<no_value_t, ::sqlpp::tag::order_by>;
+				using _recursive_traits = make_recursive_traits<Expressions...>;
+
+				using _is_dynamic = typename std::conditional<std::is_same<Database, void>::value, std::false_type, std::true_type>::type;
+
+				static_assert(_is_dynamic::value or sizeof...(Expressions), "at least one expression (e.g. a column) required in order_by()");
+
+				static_assert(not ::sqlpp::detail::has_duplicates<Expressions...>::value, "at least one duplicate argument detected in order_by()");
+
+				static_assert(::sqlpp::detail::all_t<is_expression_t<Expressions>::value...>::value, "at least one argument is not an expression in order_by()");
+
+				// Data
+				using _data_t = select_flag_list_data_t<Database, Expressions...>;
+
+				// Member implementation with data and methods
+				template<typename Policies>
+					struct _impl_t
+					{
+						template<typename Expression>
+							void add_ntc(Expression expression)
+							{
+								add<Expression, std::false_type>(expression);
+							}
+
+						template<typename Expression, typename TableCheckRequired = std::true_type>
+							void add(Expression expression)
+							{
+								static_assert(_is_dynamic::value, "add() must not be called for static order_by");
+								static_assert(is_expression_t<Expression>::value, "invalid expression argument in order_by::add()");
+								static_assert(TableCheckRequired::value or Policies::template _no_unknown_tables<Expression>::value, "expression uses tables unknown to this statement in order_by::add()");
+
+								using ok = ::sqlpp::detail::all_t<_is_dynamic::value, is_expression_t<Expression>::value>;
+
+								_add_impl(expression, ok()); // dispatch to prevent compile messages after the static_assert
+							}
+
+					private:
+						template<typename Expression>
+							void _add_impl(Expression expression, const std::true_type&)
+							{
+								return _data._dynamic_expressions.emplace_back(expression);
+							}
+
+						template<typename Expression>
+							void _add_impl(Expression expression, const std::false_type&);
+					public:
+						_data_t _data;
+					};
+
+				// Member template for adding the named member to a statement
+				template<typename Policies>
+					struct _member_t
+					{
+						using _data_t = order_by_data_t<Database, Expressions...>;
+
+						_impl_t<Policies> order_by;
+						_impl_t<Policies>& operator()() { return order_by; }
+						const _impl_t<Policies>& operator()() const { return order_by; }
+
+						template<typename T>
+							static auto _get_member(T t) -> decltype(t.order_by)
+							{
+								return t.order_by;
+							}
+					};
+
+				template<typename Policies>
+					struct _methods_t
+					{
+					};
+			};
+
+		// NO ORDER BY YET
 		struct no_order_by_t
 		{
 			using _traits = make_traits<no_value_t, ::sqlpp::tag::noop>;
 			using _recursive_traits = make_recursive_traits<>;
 
+			// Data
+			using _data_t = no_data_t;
+
+			// Member implementation with data and methods
+			template<typename Policies>
+				struct _impl_t
+				{
+					_data_t _data;
+				};
+
+			// Member template for adding the named member to a statement
+			template<typename Policies>
+				struct _member_t
+				{
+					using _data_t = no_data_t;
+
+					_impl_t<Policies> no_order_by;
+					_impl_t<Policies>& operator()() { return no_order_by; }
+					const _impl_t<Policies>& operator()() const { return no_order_by; }
+
+					template<typename T>
+						static auto _get_member(T t) -> decltype(t.no_order_by)
+						{
+							return t.no_order_by;
+						}
+				};
+
 			template<typename Policies>
 				struct _methods_t
 				{
@@ -117,7 +177,7 @@ namespace sqlpp
 						auto order_by(Args... args)
 						-> _new_statement_t<order_by_t<void, Args...>>
 						{
-							return { *static_cast<typename Policies::_statement_t*>(this), order_by_t<void, Args...>{args...} };
+							return { *static_cast<typename Policies::_statement_t*>(this), order_by_data_t<void, Args...>{args...} };
 						}
 
 					template<typename... Args>
@@ -125,16 +185,16 @@ namespace sqlpp
 						-> _new_statement_t<order_by_t<_database_t, Args...>>
 						{
 							static_assert(not std::is_same<_database_t, void>::value, "dynamic_order_by must not be called in a static statement");
-							return { *static_cast<typename Policies::_statement_t*>(this), vendor::order_by_t<_database_t, Args...>{args...} };
+							return { *static_cast<typename Policies::_statement_t*>(this), order_by_data_t<_database_t, Args...>{args...} };
 						}
 				};
 		};
 
 		// Interpreters
 		template<typename Context, typename Database, typename... Expressions>
-			struct serializer_t<Context, order_by_t<Database, Expressions...>>
+			struct serializer_t<Context, order_by_data_t<Database, Expressions...>>
 			{
-				using T = order_by_t<Database, Expressions...>;
+				using T = order_by_data_t<Database, Expressions...>;
 
 				static Context& _(const T& t, Context& context)
 				{
@@ -148,18 +208,6 @@ namespace sqlpp
 					return context;
 				}
 			};
-
-		template<typename Context>
-			struct serializer_t<Context, no_order_by_t>
-			{
-				using T = no_order_by_t;
-
-				static Context& _(const T& t, Context& context)
-				{
-					return context;
-				}
-			};
-
 	}
 }
 

include/sqlpp11/vendor/select_flag_list.h

@@ -38,7 +38,7 @@ namespace sqlpp
 {
 	namespace vendor
 	{
-		// SELECTED COLUMNS DATA
+		// SELECTED FLAGS DATA
 		template<typename Database, typename... Flags>
 			struct select_flag_list_data_t
 			{

include/sqlpp11/vendor/where.h

@@ -38,6 +38,7 @@ namespace sqlpp
 {
 	namespace vendor
 	{
+		// WHERE DATA
 		template<typename Database, typename... Expressions>
 			struct where_data_t
 			{