More flexible array retrieval + *vector support.

pgsql/Pgsql_oids.h

@@ -2,6 +2,8 @@
 #define PGSQL_OIDS_H
 
 #include <libpq-fe.h>
+#include <cstdint>
+#include <QDateTime>
 
 namespace Pgsql {
 	constexpr Oid bool_oid = 16;
@@ -141,6 +143,47 @@ namespace Pgsql {
 	Oid ElemOidFromArrayOid(Oid oid);
 	Oid ArrayOidFromElemOid(Oid oid);
 
+	template <typename T>
+	class OidFor {
+	public:
+		static Oid elem();
+		static Oid array();
+	};
+
+	template <>
+	class OidFor<int16_t> {
+	public:
+		static Oid elem() { return int2_oid; }
+		static Oid array() { return int2_array_oid; }
+	};
+
+	template <>
+	class OidFor<int32_t> {
+	public:
+		static Oid elem() { return int4_oid; }
+		static Oid array() { return int4_array_oid; }
+	};
+
+	template <>
+	class OidFor<unsigned int> {
+	public:
+		static Oid elem() { return oid_oid; }
+		static Oid array() { return oid_array_oid; }
+	};
+
+	template <>
+	class OidFor<QDateTime> {
+	public:
+		static Oid elem() { return timestamptz_oid; }
+		static Oid array() { return timestamptz_array_oid; }
+	};
+//	template <>
+//	class OidFor<> {
+//	public:
+//		static Oid elem() { return _oid; }
+//		static Oid array() { return _array_oid; }
+//	};
+
 } // end of namespace Pgsql
 
 #endif // PGSQL_OIDS_H