TOracleObject.Assign: assigning descendant to ancestor

[Worad]

Good evening

1. How do I typecast one instance of TOracleObject to another with other type (ancestor to descendant)?

2. How do I use sys.anydata type with DOA 4.0?

3. I have a problem when I tryed to assign an Oracle Object descendant represented by TOracleObject to ancestor.

Problem decription.

I have the followning types in Oracle 10g DB:

create or replace type TAncestor as object
(
stub char(1)
) not final;
/
create or replace type TDescendant under TAncestor
(
FValue varchar2(4000)
);

In a Delphi7 I have the following code:
procedure TestAssign(Session: TOracleSession);
var
S, D, T: TOracleObject;
begin
T := TOracleObject.Create(Session, 'TAncestor', '');
S := TOracleObject.Create(Session, 'TDescendant', '');
D := TOracleObject.Create(Session, 'TDescendant', '');
S.SetAttr('FValue', 'yes');
T.Assign(S);
D.Assign(T);
// And D.AttrByName('FValue') not equal 'yes'.
// D.AttrByName('FValue') is ''.
FreeAndNil(S);
FreeAndNil(T);
FreeAndNil(D);
end;

Why does D.AttrByName('FValue') return '' instead of 'yes'?

 

[Marco Kalter]

I'm afraid this is not possible. You cannot typecast or assign different object types (though Oracle apparently does not raise an exception), and you cannot use the anydata type.

 

[Worad]

Originally posted by Marco Kalter:
I'm afraid this is not possible. You cannot typecast or assign different object types (though Oracle apparently does not raise an exception), and you cannot use the anydata type.

Hi
In Oracle 10g in OCI documentation "Oracle