Object extensions Oracle8 - a few questions

From: Michal Prinke <bogien_at_fanthom.math.put.poznan.pl>
Date: Sun, 27 May 2001 21:51:15 +0000 (UTC)
Message-ID: <9erssj$mbk$1@main.amu.edu.pl>

At the moment I'm learning how to use the object extensions for Oracle8. I own Personal Oracle8i 8.1.6 running on Win98SE. I was wondering how to do a few things...

Suppose we already have the following structures (don't care about the syntax - it is simplified):

create type BOOKS as table of ref BOOK;
create type BOOK as object (
  TITLE varchar2(50),
  COUNTER number(5),
  SEQUELS BOOKS,
  member procedure DO_IT
);
create table LIBRARY of BOOK store nested table SEQUELS as SSS;

My questions are:
1. how to call the method DO_IT() of a specific BOOK from

   the LIBRARY, which TITLE is '101 dalmatians'? Is there    something like:

   exec l.do_it() from library l where title = '101 dalmatians'

2. is it possible for the method DO_IT() to change some fields

   of an object to which it belongs? Suppose it has to increment    its field COUNTER. Can i do it any simpler than:

   fetch book from library into variable where title = '...'    variable.do_it()
   replace book in library with variable where title = '...'

3. suppose DO_IT() has to output (using dbms_output.put_line())

   the TITLEs of all the SEQUELS of a BOOK to which it belongs.    How to write the method then? How to perform a SELECT    on the nested table SEQUELS, when it is still treated as    a normal field, not a table? I've tried:

   create type body BOOK is

     member procedure DO_IT is
       cursor MY_CURSOR is select deref(a) from table(SEQUELS) a;
       X MY_CURSOR%ROWTYPE;
     begin
       for X in MY_CURSOR loop
         dbms_output.put_line(X.TITLE);
       end loop;
     end;

   end;

   ...but it didn't work.

Thanks for attention,

--
   @_/       Michal "Bogien/Bogna" Prinke
  \/\ _
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     /  oo   email: bogien_at_conecto.pl, tel: 830-17-21, era gsm: 606 48-75-34
    oo       g-g: 160130, www: http://www.math.put.poznan.pl/~bogien

Received on Sun May 27 2001 - 16:51:15 CDT