Added to functions to Pgsql::Result to help in doing smart things based on a result.

- ftable, return from which table the column in the result originates
- ftableCol, returns the column number within that table (attnum)
Ofcourse columns can also be expressions in which case these functions return InvalidOid and 0.

pgsql/Pgsql_Result.h

@@ -123,6 +123,15 @@ namespace Pgsql {
 		Oid type(int col) const;
 		bool null(int col, int row) const;
 
+		/// Return the oid of the table this is a column of
+		/// when the column isn't a table column InvalidOid is returned
+		/// when col is out of range a std::range_error is thrown
+		Oid ftable(int col) const;
+		/// Returns the attnum of col in its table, attnum is negative for system cols like oid
+		/// It is positive for user columns, 0 signals there is no direct table column mapping
+		/// when col is out of range a std::range_error is thrown
+		int ftableCol(int col) const;
+
 
 	//		iterator begin();
 	private: