How to Dynamically read Collections?

Question

Hi,
I want to read collections dynamically. I have a requirement where I need to take any COMPLEX collection and goto the leaf node and get the results. I'm able to get the attributes using "ALL_TYPES" and "ALL_TYPE_ATTRS" etc but how can I read dynamically?
for example I've a following simple type declared but is giving error. I hope any proposed solution will work with collection "TYPE T IS TABLE OF R" as well.
DECLARE
TYPE R IS RECORD (X VARCHAR2(1), Y VARCHAR2(1));
VAR R;
TST VARCHAR2(100);
BEGIN
VAR.X := 'I';
VAR.Y := 'J';
EXECUTE IMMEDIATE 'SELECT VAR.X FROM DUAL' INTO TST;
DBMS_OUTPUT.PUT_LINE(TST);
END;
Thanks

Answer 1

So, let suppose I want to read Test6.Test5(1).Test4.Five Dynamically? How can i do that if objects are populated? Here's one way:
SQL> create type test1 as object (one date);
Type created.
SQL> create type test2 as object (two number, three varchar2(10), four test1);
Type created.
SQL> create type test3 as table of test2;
Type created.
SQL> create type test4 as object (five varchar2(1), six date, seven test3);
Type created.
SQL> create type test5 as table of test4;
Type created.
SQL> create type test6 as object (eight test5);
Type created.
SQL> var cur refcursor
SQL> declare
  procedure testobj (myobj test6)
  is
    myval   varchar2 (10);
  begin
    open :cur for select x.column_value.getrootelement() || ': ' || x.column_value.extract('*/text()').getstringval() result from xmltable ('*' passing sys_xmlgen (myobj).extract('ROW//*')) x;
  end;
begin
  testobj (test6 (test5(test4(1,sysdate, test3(test2(5,67,null))))));
end;
PL/SQL procedure successfully completed.
SQL> print cur
RESULT                                                                                                                           
EIGHT:                                                                                                                           
TEST4:                                                                                                                           
FIVE: 1                                                                                                                          
SIX: 22/03/2012 18:16:23                                                                                                         
SEVEN:                                                                                                                           
TEST2:                                                                                                                           
TWO: 5                                                                                                                           
THREE: 67                                                                                                                        
8 rows selected.