
Command Query
=============

A query is a command which does not change the contents of
the underlying data source.

This is a subclass of the command class.

Constructors
============
   Open       - The open command implemented in the connection
                class creates a query instance specific for the 
                selected connection.
                Initiate a query inst ance. The optionaly given
                command may be prepared by the underlying
                data source.         
                Only a reference on the object will be returned.
   Close      - Dstroys the query instance. 
   

Attributes
==========
   State      - Open/Closed
   Num_Params - Number of parameter marks (?) in the sql statement,
                available if State = Open
  
Methods
=======

   Execute   - Execute the command on the underlying data source.
               Returns a Result_Set

Interfaces
==========

Example
======= 

  Con      : Connection.ODBC.Instance;
  Qry      : Query.Handle;
  X        : Integer;
begin

  Connection.Open (Con, "......");
  
  Qry := Query.Open (Con, "SELECT ID FROM EMPLOYEES WHERE ID > ?");
  Set(Qry, 1, 1002);  -- Sets the parameter 1 to 1002

  Result := Execute (Qry);
 
  ..................

  Close (Qry);

  COnnection.Close (Conn);

end ;


