Field Class
===========

A field maintains the actual value of a field in the 
result set.


Constructors
============

     Create  - Returns a field handle
     Destroy -

Attributes
==========

     Name   - Name of a field
     Pos    - Position of a field

Methods
=======
 
     Value  - Set or get a value. This procedure/function
              should be provided for all common Ada 95 data
              types.
              
              Value( in out field, integer )
              Value( field ) return integer;

Interfaces
==========

Example
======= 

   C      : Connection.ODBC.Instance;
   Q      : Query.Handle;
   Result : Result_Set.Instance;

   Connection.Open (C, ".....");

   -- this dispatches depending on the connection type into 
   -- different implementations of a query.
   Q := Query.Open ( C, "SELECT FIRST_NAME, LAST_NAME FROM TABLE WHERE EMPNO>?");
   Set( Q, 1, 2001 );

   ......
   
   -- execute the result set but using a handle makes the code
   -- independant from the implementation of the connction
   Result := Execute(Q);

   declare
      last_name  : Field.Handle := Field.Create( Result, "LAST_NAME " );
      first_Name : Field.Handle := Field.Create( Result, 1 );
   begin
      while not Result_Set.End_Of_Result_Set (Result) loop

         Text_IO.Put( Value( last_name ) ); 
	 Text_IO.Put( Value( first_name ) );

         Result_Set.Next (Result);
      end loop;
   exception 
      when Connection_Closed =>
        .....
      when Others =>
        .....
   end ;

   Result_Set.Drop (Result);  -- this drops the fields as well.
   Query.Close (Q);
   Conection.CLose (C);
