Having Trouble with nested Case Statements

Question

Hi Folks,
I'm having trouble getting my head round nested case statements. For the life of me I cannot see what I'm missing here (unless my approach is all wrong).
Any help much appreciated.
Script:
set serveroutput on format wrapped
set feedback off
set linesize 150
DECLARE
/* Set supported version here */
ora_version VARCHAR2(4);
unsupp_version EXCEPTION;
/* Archive Log Info */
db_log_mode VARCHAR2(12);
BEGIN
SELECT SUBSTR(VERSION, 1, 4)
INTO ora_version
FROM v$instance;
SELECT log_mode
INTO db_log_mode
FROM v$database;
CASE
WHEN ora_version = '10.2' THEN
DECLARE
TYPE t_db IS RECORD(
dflsh VARCHAR2(3),
dcscn NUMBER);
v_db t_db;
BEGIN
CASE
WHEN db_log_mode = 'ARCHIVELOG' THEN
EXECUTE IMMEDIATE 'SELECT INITCAP(flashback_on), current_scn FROM v$database'
INTO v_db;
DBMS_OUTPUT.PUT_LINE(' Flashback On : ' || v_db.dflsh);
DBMS_OUTPUT.PUT_LINE(' Current SCN : ' || v_db.dcscn);
DBMS_OUTPUT.PUT_LINE(' Log Mode : ' || db_log_mode);
DBMS_OUTPUT.PUT_LINE(' Version : ' || ora_version);
END;
ELSE
DBMS_OUTPUT.PUT_LINE(' Log Mode : ' || db_log_mode);
DBMS_OUTPUT.PUT_LINE(' Version : ' || ora_version);
END CASE;
END;
WHEN ora_version = '9.2' THEN
DECLARE
TYPE t_db IS RECORD(
dcscn NUMBER);
v_db t_db;
BEGIN
CASE
WHEN db_log_mode = 'ARCHIVELOG' THEN
EXECUTE IMMEDIATE 'SELECT current_scn FROM v$database'
INTO v_db;
DBMS_OUTPUT.PUT_LINE(' Current SCN : ' || v_db.dcscn);
DBMS_OUTPUT.PUT_LINE(' Log Mode : ' || db_log_mode);
DBMS_OUTPUT.PUT_LINE(' Version : ' || ora_version);
END;
ELSE
DBMS_OUTPUT.PUT_LINE(' Log Mode : ' || db_log_mode);
DBMS_OUTPUT.PUT_LINE(' Version : ' || ora_version);
END CASE;
END;
ELSE
RAISE unsupp_version;
END CASE;
EXCEPTION
WHEN unsupp_version THEN
DBMS_OUTPUT.PUT_LINE('');
DBMS_OUTPUT.PUT_LINE(' Unsupported Version '||ora_version||' !');
DBMS_OUTPUT.PUT_LINE('');
END;
set linesize 80
set feedback on
set serveroutput off
Gives errors:
END;
ERROR at line 31:
ORA-06550: line 31, column 7:
PLS-00103: Encountered the symbol ";" when expecting one of the following:
case
ORA-06550: line 37, column 1:
PLS-00103: Encountered the symbol "WHEN"
ORA-06550: line 50, column 28:
PLS-00103: Encountered the symbol ";" when expecting one of the following:
case
Edited by: milkyjoe on 28-Apr-2010 05:38

Answer 1

Hi,
Never write, much less post, unformatted code.
Indent the code to show the extent of multi-line structures like BEGIN and CASE.
For example:
DECLARE
     /* Set supported version here */
     ora_version       VARCHAR2 (4);
     unsupp_version       EXCEPTION;
     /* Archive Log Info */
     db_log_mode      VARCHAR2 (12);
BEGIN
     SELECT     SUBSTR(VERSION, 1, 4)
     INTO     ora_version
     FROM     v$instance;
     SELECT     log_mode
     INTO     db_log_mode
     FROM     v$database;
     CASE
         WHEN  ora_version = '10.2' THEN
          DECLARE
              TYPE t_db IS RECORD(
                         dflsh     VARCHAR2(3),
                         dcscn      NUMBER);
              v_db t_db;
          BEGIN
              CASE
                  WHEN db_log_mode = 'ARCHIVELOG' THEN
                   EXECUTE IMMEDIATE 'SELECT INITCAP(flashback_on), current_scn FROM v$database'
                                       INTO v_db;
                   DBMS_OUTPUT.PUT_LINE(' Flashback On : ' || v_db.dflsh);
                   DBMS_OUTPUT.PUT_LINE(' Current SCN : ' || v_db.dcscn);
                   DBMS_OUTPUT.PUT_LINE(' Log Mode : ' || db_log_mode);
                   DBMS_OUTPUT.PUT_LINE(' Version : ' || ora_version);
              END;
...The code above is what you posted, with some whitespace added.
The error is much clearer; the last CASE statement concludes with END, but CASE blocks always have to conclude with END CASE .
Why are you using a nested BEGIN block in the code above? Are you plannning to add an EXCEPTION handler later?
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