Hi
The anonnymous block at the bottom of my email is just a little test driver.
Basically, I don't use subtyping here. I just override the default
constructor.
If I don't implement a constructor at all, I would look like this:
CREATE OR REPLACE TYPE tVNR AS OBJECT
(
vVNR VARCHAR2(14),
MEMBER FUNCTION getVNR
RETURN VARCHAR2
) INSTANTIABLE FINAL;
CREATE OR REPLACE TYPE BODY tVNR AS
MEMBER FUNCTION getVNR RETURN VARCHAR2 IS
BEGIN
RETURN SELF.vVNR;
END;
END;
And I would get a hidden, system provided default constructor.
That would allow me to do the following (tested it):
declare
vVNR tVNR;
begin
vVNR := new tVNR('12345678901');
dbms_output.put_line(vVNR.getVNR());
end;
And I would get the output:
12345678901
Unfortunately, that doesn't give me any control regarding the initialization
of vVNR.
Explanation: VNR = "Versichertennummer", which is kind of the Swiss analog
to the
US Social Security ID, only less unique ;).
We don't use Object Relational features IN the database. Just plain
relational tables.
What we would like to use are Object Types to encapsulate certain things
like the above
shown VNR to ensure data integrity during data conversion for PL/SQL
programs using
these types. It's more of a guideline where the developers are constrained
to use the
types for certain stuff.
Enjoy your day,
Stefan Jahnke
Consultant
BOV Aktiengesellschaft
Tel.: +49 201/45 13-289
mailto:[EMAIL PROTECTED]
http://www.bov.de
Abonnieren Sie unseren Newsletter: http://www.bov.de/enews
Kosten senken - strategische IT-Ziele erreichen! BOV Microsoft Day am
24.07.03 in Essen. Anmeldung unter http://www.bov.de/microsoft-day oder
mailto:[EMAIL PROTECTED]
Wie Sie wissen, koennen ueber das Internet versandte E-Mails leicht unter
fremden Namen erstellt oder manipuliert werden. Aus diesem Grunde bitten wir
um Verstaendnis dafuer, dass wir zu Ihrem und unserem Schutz die rechtliche
Verbindlichkeit der vorstehenden Erklaerungen und Aeusserungen
ausschliessen.
As you are probably aware, e-mails sent via the Internet can easily be
copied or manipulated by third parties. For this reason we would ask for
your understanding that, for your own protection and ours, we must decline
all legal responsibility for the validity of the statements and comments
given above.
-----Ursprüngliche Nachricht-----
Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Gesendet: Dienstag, 15. Juli 2003 14:05
An: Multiple recipients of list ORACLE-L
Betreff: Re: Object Types in PL/SQL
if im reading your code right... looks like your overriding in an anonymous
block. in most OO languages overriding is done by a child class. i dont see
any subclassing here? didnt they add sub-types and 'extends' to 9.2?
btw, are you using object oriented design in your database? How efficient do
you find that?
>
> From: Stefan Jahnke <[EMAIL PROTECTED]>
> Date: 2003/07/15 Tue AM 06:49:25 EDT
> To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
> Subject: Object Types in PL/SQL
>
> Hi list
>
> I have a problem regardint PL/SQL Object Types. According to the fine
> manual, it should be
> possible to override the default constructor (I'm on 9.2.0.3.0 Win2k). I
did
> that, Object Type
> compiles without complaints:
>
> CREATE OR REPLACE TYPE tVNR AS OBJECT
> (
>
> vVNR VARCHAR2(14),
>
> CONSTRUCTOR FUNCTION tVNR(piVNR VARCHAR2)
> RETURN SELF AS RESULT,
>
> MEMBER FUNCTION getVNR
> RETURN VARCHAR2
>
> ) INSTANTIABLE FINAL;
>
> CREATE OR REPLACE TYPE BODY tVNR AS
>
> CONSTRUCTOR FUNCTION tVNR(piVNR VARCHAR2)
> RETURN SELF AS RESULT IS
> BEGIN
> IF (LENGTH(piVNR)=11) THEN
> SELF.vVNR := SUBSTR(piVNR,1,4) || '.' || SUBSTR(piVNR,5,4) || '.' ||
> SUBSTR(piVNR,9,3);
> ELSE
> SELF.vVNR := 'invalid';
> END IF;
> RETURN;
> END;
>
> MEMBER FUNCTION getVNR RETURN VARCHAR2 IS
> BEGIN
> RETURN SELF.vVNR;
> END;
> END;
>
> Now, everytime I want to create an object like this:
>
> declare
> vVNR tVNR;
> begin
> vVNR := new tVNR('12345678901');
> dbms_output.put_line(vVNR.getVNR());
> end;
>
> I get the following error message:
>
> ERROR at line 4:
> ORA-06550: line 4, column 15:
> PLS-00307: too many declarations of 'TVNR' match this call
> ORA-06550: line 4, column 3:
> PL/SQL: Statement ignored
>
> Looks to me like the PL/SQL enginge isn't able to distinguish the default
> constructor from the
> overridden (my) version, since they have the same signature (of course).
>
> Any input ? I couldn't find ANY descenct hints in the fine manual or the
> Feuerstein book :(.
>
> TIA,
> Stefan
>
>
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Stefan Jahnke
> INET: [EMAIL PROTECTED]
>
> Fat City Network Services -- 858-538-5051 http://www.fatcity.com
> San Diego, California -- Mailing list and web hosting services
> ---------------------------------------------------------------------
> To REMOVE yourself from this mailing list, send an E-Mail message
> to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
> the message BODY, include a line containing: UNSUB ORACLE-L
> (or the name of mailing list you want to be removed from). You may
> also send the HELP command for other information (like subscribing).
>
>
--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: <[EMAIL PROTECTED]
INET: [EMAIL PROTECTED]
Fat City Network Services -- 858-538-5051 http://www.fatcity.com
San Diego, California -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: Stefan Jahnke
INET: [EMAIL PROTECTED]
Fat City Network Services -- 858-538-5051 http://www.fatcity.com
San Diego, California -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
