Oracle PL/SQL Programming: A Developer's Workbook

Expert

Q:
23-20.	The most elegant (not necessarily the most efficient) solution involves recursion: /* Filename on web page: println.sp */ CREATE OR REPLACE PROCEDURE println (val IN VARCHAR2) IS BEGIN /* Don't display lines longer than 80 characters; they are hard to read. */ IF LENGTH (val) > 80 THEN DBMS_OUTPUT.PUT_LINE (SUBSTR (val, 1, 80)); println (SUBSTR (val, 81)); ELSE DBMS_OUTPUT.PUT_LINE (val); END IF; END; /
Q:
23-21.	To obtain this behavior, add the following exception section to the implementation of println: EXCEPTION WHEN OTHERS THEN DBMS_OUTPUT.ENABLE (1000000); println (val); END; / In other words, if any problem occurs, expand the buffer to its maximum size and then try, try again.
Q:
23-22.	The most interesting aspect of the solution is the implementation of the Boolean overloading. Here is one possible approach: /* Filename on web page: print.pkg */ CREATE OR REPLACE PACKAGE BODY print IS PROCEDURE ln (val IN VARCHAR2) IS BEGIN IF LENGTH (val) > 80 THEN DBMS_OUTPUT.PUT_LINE (SUBSTR (val, 1, 80)); ln (SUBSTR (val, 81)); ELSE DBMS_OUTPUT.PUT_LINE (val); END IF; EXCEPTION WHEN OTHERS THEN DBMS_OUTPUT.ENABLE (1000000); ln (val); END; PROCEDURE ln (val IN DATE) IS BEGIN ln (TO_CHAR (val, 'MM/DD/YYYY HH24:MI:SS')); END; PROCEDURE ln (val IN NUMBER) IS BEGIN ln (TO_CHAR (val)); ...