Oracle PL/SQL Programming: A Developer's Workbook

Expert

Q:
28-33.	The following function is a possible solution for this problem. Note the use of the SUBSTR function to perform ASCII-to-HEX conversion: /* Filename on web page: cgi_encode.sf */ CREATE OR REPLACE FUNCTION cgi_encode (s in VARCHAR2) RETURN VARCHAR2 is ret_val VARCHAR2(32762) DEFAULT NULL; c CHAR(1); ld NUMBER DEFAULT 0; td NUMBER DEFAULT 0; a2h VARCHAR2(20) := '0123456789ABCDEF'; BEGIN FOR i IN 1..LENGTH(s) LOOP c := SUBSTR(s,i,1); IF ((UPPER(c) >= 'A' ) and ( UPPER(c) <= 'Z')) OR ((c >= '0') AND (c <= '9')) OR (c = '_') THEN ret_val := ret_val || c; ELSEIF c = ' ' then ret_val := ret_val || '+'; ELSE ld := FLOOR( ASCII ( c ) / 16 ); td := ASCII( c ) - 16*ld; ret_val := ret_val || '%'; ret_val := ret_val || SUBSTR(a2h,ld+1,1); ret_val := ret_val || SUBSTR(a2h,td+1,1); END IF; END LOOP; RETURN ret_val; EXCEPTION WHEN OTHERS THEN RETURN 'CONVERSION+ERROR'; END;
Q:
28-34.	The most likely cause of this problem is a buffer overflow. At the beginning of the time period, when there were just a few records, everything seemed to work fine. As more records were added, however, the system became noticeably slower. Finally, it exceeded the size of the HTML output buffer. Unfortunately, there is no PL/SQL workaround to this problem. A reasonable approach is to either break the file into sections or replace the PL/SQL procedure with a nonbuffered language such as Perl.
Q:
28-35.	The original ...