ch04_case03.sql

OReilly Oracle PL SQL Programming第4版源代码

/* Simple CASE expression example */
DECLARE
   boolean_true BOOLEAN := TRUE;
   boolean_false BOOLEAN := FALSE;
   boolean_null BOOLEAN;

   FUNCTION boolean_to_varchar2 (flag IN BOOLEAN) RETURN VARCHAR2 IS
   BEGIN
      RETURN
      CASE flag
      WHEN TRUE THEN 'True'
      WHEN FALSE THEN 'False'
      ELSE 'NULL' END;
   END;

BEGIN
   DBMS_OUTPUT.PUT_LINE(boolean_to_varchar2(boolean_true));
   DBMS_OUTPUT.PUT_LINE(boolean_to_varchar2(boolean_false));
   DBMS_OUTPUT.PUT_LINE(boolean_to_varchar2(boolean_null));
END;
/


/*======================================================================
| Supplement to the third edition of Oracle PL/SQL Programming by Steven
| Feuerstein with Bill Pribyl, Copyright (c) 1997-2002 O'Reilly &
| Associates, Inc. To submit corrections or find more code samples visit
| http://www.oreilly.com/catalog/oraclep3/
*/