Added more checks for database traits

include/sqlpp11/avg.h

@@ -37,7 +37,7 @@ namespace sqlpp
 		template<typename Expr>
 		struct avg_t: public boolean::template operators<avg_t<Expr>>
 		{
-			static_assert(is_value_t<Expr>::value, "avg() requires a value expression as argument");
+			static_assert(is_numeric_t<Expr>::value, "avg() requires a value expression as argument");
 
 			struct _value_type: public Expr::_value_type::_base_value_type
 			{
@@ -71,6 +71,7 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
+					static_assert(Db::_supports_avg, "avg() not supported by current database");
 					os << "AVG(";
 					_expr.serialize(os, db);
 					os << ")";

include/sqlpp11/count.h

@@ -71,6 +71,7 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
+					static_assert(Db::_supports_count, "count() not supported by current database");
 					os << "COUNT(";
 					_expr.serialize(os, db);
 					os << ")";

include/sqlpp11/exists.h

@@ -71,6 +71,7 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
+					static_assert(Db::_supports_exists, "exists() not supported by current database");
 					os << "EXISTS(";
 					_select.serialize(os, db);
 					os << ")";

include/sqlpp11/group_by.h

@@ -57,6 +57,7 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
+					static_assert(Db::_supports_group_by, "group_by() not supported by current database");
 					os << " GROUP BY ";
 					detail::serialize_tuple(os, db, _expressions, ',');
 				}
@@ -80,6 +81,7 @@ namespace sqlpp
 
 			void serialize(std::ostream& os, Db& db) const
 			{
+				static_assert(Db::_supports_group_by, "group_by() not supported by current database");
 				if (_expressions.empty())
 					return;
 				os << " GROUP BY ";

include/sqlpp11/having.h

@@ -46,6 +46,7 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
+					static_assert(Db::_supports_having, "having() not supported by current database");
 					os << " HAVING ";
 					_expr.serialize(os, db);
 				}
@@ -69,6 +70,7 @@ namespace sqlpp
 
 		void serialize(std::ostream& os, Db& db) const
 		{
+			static_assert(Db::_supports_having, "having() not supported by current database");
 			if (_conditions.empty())
 				return;
 

include/sqlpp11/in.h

@@ -35,10 +35,10 @@ namespace sqlpp
 {
 	namespace detail
 	{
-		template<bool not_inverted, typename Operand, typename... Args>
+		template<bool NotInverted, typename Operand, typename... Args>
-		struct in_t: public Operand::_value_type::template operators<in_t<not_inverted, Operand, Args...>>
+		struct in_t: public Operand::_value_type::template operators<in_t<NotInverted, Operand, Args...>>
 		{
-			static constexpr bool inverted = not not_inverted;
+			static constexpr bool _inverted = not NotInverted;
 			static_assert(sizeof...(Args) > 0, "in() requires at least one argument");
 
 			struct _value_type: public Operand::_value_type::_base_value_type
@@ -48,7 +48,7 @@ namespace sqlpp
 
 			struct _name_t
 			{
-				static constexpr const char* _get_name() { return inverted ? "NOT IN" : "IN"; }
+				static constexpr const char* _get_name() { return _inverted ? "NOT IN" : "IN"; }
 				template<typename T>
 					struct _member_t
 					{
@@ -75,8 +75,10 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
+					static_assert(NotInverted and Db::_supports_in
+							or _inverted and Db::_supports_not_in, "in() not supported by current database");
 					_operand.serialize(os, db);
-					os << (inverted ? " NOT IN(" : " IN(");
+					os << (_inverted ? " NOT IN(" : " IN(");
 					detail::serialize_tuple(os, db, _args, ',');
 					os << ")";
 				}

include/sqlpp11/like.h

@@ -75,6 +75,7 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
+					static_assert(Db::_supports_like, "like() not supported by current database");
 					_operand.serialize(os, db);
 					os << " LIKE(";
 					_pattern.serialize(os, db);

include/sqlpp11/limit.h

@@ -40,6 +40,7 @@ namespace sqlpp
 		template<typename Db>
 			void serialize(std::ostream& os, Db& db) const
 			{
+				static_assert(Db::_supports_limit, "limit not supported by current database");
 				os << " LIMIT " << _limit;
 			}
 
@@ -69,6 +70,7 @@ namespace sqlpp
 		template<typename Db>
 			void serialize(std::ostream& os, Db& db) const
 			{
+				static_assert(Db::_supports_limit, "limit not supported by current database");
 				if (_limit > 0)
 					os << " LIMIT " << _limit;
 			}

include/sqlpp11/max.h

@@ -71,6 +71,7 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
+					static_assert(Db::_supports_max, "max not supported by current database");
 					os << "MAX(";
 					_expr.serialize(os, db);
 					os << ")";

include/sqlpp11/min.h

@@ -71,6 +71,7 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
+					static_assert(Db::_supports_min, "min not supported by current database");
 					os << "MIN(";
 					_expr.serialize(os, db);
 					os << ")";

include/sqlpp11/order_by.h

@@ -54,6 +54,7 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
+					static_assert(Db::_supports_order_by, "order by not supported by current database");
 					os << " ORDER BY ";
 					detail::serialize_tuple(os, db, _orderExpressions, ',');
 				}
@@ -76,6 +77,7 @@ namespace sqlpp
 
 			void serialize(std::ostream& os, Db& db) const
 			{
+				static_assert(Db::_supports_order_by, "order by not supported by current database");
 				if (_expressions.empty())
 					return;
 				os << " ORDER BY ";

include/sqlpp11/select_pseudo_table.h

@@ -69,6 +69,7 @@ namespace sqlpp
 		template<typename Db>
 			void serialize(std::ostream& os, Db& db) const
 			{
+				static_assert(Db::_supports_select_as_table, "select as table not supported by current database");
 				_select.serialize(os, db);
 			}
 

include/sqlpp11/sum.h

@@ -37,7 +37,7 @@ namespace sqlpp
 		template<typename Expr>
 		struct max_t: public boolean::template operators<max_t<Expr>>
 		{
-			static_assert(is_value_t<Expr>::value, "max() requires a value expression as argument");
+			static_assert(is_numeric_t<Expr>::value, "sum() requires a numeric expression as argument");
 
 			struct _value_type: public Expr::_value_type::_base_value_type
 			{
@@ -46,7 +46,7 @@ namespace sqlpp
 
 			struct _name_t
 			{
-				static constexpr const char* _get_name() { return "MAX"; }
+				static constexpr const char* _get_name() { return "SUM"; }
 				template<typename T>
 					struct _member_t
 					{
@@ -71,7 +71,8 @@ namespace sqlpp
 			template<typename Db>
 				void serialize(std::ostream& os, Db& db) const
 				{
-					os << "MAX(";
+					static_assert(Db::_supports_sum, "sum not supported by current database");
+					os << "SUM(";
 					_expr.serialize(os, db);
 					os << ")";
 				}

tests/SelectTest.cpp

@@ -32,10 +32,34 @@
 class DbMock: public sqlpp::connection
 {
 public:
-	static constexpr bool _supports_any = true;
+	// join types
+	static constexpr bool _supports_inner_join = true;
+	static constexpr bool _supports_outer_join = true;
+	static constexpr bool _supports_left_outer_join = true;
+	static constexpr bool _supports_right_outer_join = true;
 
+	// functions
+	static constexpr bool _supports_avg = true;
+	static constexpr bool _supports_count = true;
+	static constexpr bool _supports_exists = true;
+	static constexpr bool _supports_like = true;
+	static constexpr bool _supports_in = true;
+	static constexpr bool _supports_max = true;
+	static constexpr bool _supports_min = true;
+	static constexpr bool _supports_not_in = true;
+	static constexpr bool _supports_sum = true;
+
+	// select
+	static constexpr bool _supports_group_by = true;
+	static constexpr bool _supports_having = true;
+	static constexpr bool _supports_limit = true;
+	static constexpr bool _supports_order_by = true;
+	static constexpr bool _supports_select_as_table = true;
+
+	static constexpr bool _supports_some = true;
+	static constexpr bool _supports_any = true;
+	static constexpr bool _use_concat_operator = true;
 	static constexpr bool _use_concat_function = true;
-	static constexpr bool _use_concat_operator = false;
 
 	const std::string& escape(const std::string& text) { return text; }
 };