Skip to Main Content
Oracle PL/SQL Programming: A Developer's Workbook
book

Oracle PL/SQL Programming: A Developer's Workbook

by Steven Feuerstein, Andrew Odewahn
May 2000
Intermediate to advanced content levelIntermediate to advanced
594 pages
11h 32m
English
O'Reilly Media, Inc.
Content preview from Oracle PL/SQL Programming: A Developer's Workbook

Expert

Q:

2-22.

The first two rewrites (a and b) have just one way out, but they do not accurately reflect the processing that took place in the original. What if years_in is 3? Rewrite (d) correctly stops the loop from continuing if yearnum exceeds the value of years_in, but it still has two ways out (with the addition of the EXIT WHEN statement). Rewrite (c) is the only one that is both logically equivalent and well-structured (one way in, one way out).

Q:

2-23.

It executes an infinite number of times; this is an infinite WHILE loop. The local module called inside the loop never returns NULL for step_out, so next_analysis_step is never NULL. The analysis_cursor%NOTFOUND attribute returns TRUE, but no exception is raised even though you are fetching past the end of the result set. Thus, the loop never terminates.

Q:

2-24.

At first glance, you might think it best to use the numeric FOR loop, as shown here:

PACKAGE BODY company_pkg
IS
   TYPE ids_tabtype IS TABLE OF INTEGER
      INDEX BY BINARY_INTEGER;

   PROCEDURE close_all (company_ids IN ids_tabtype) IS
   BEGIN
      FOR id_ind IN company_ids.FIRST .. company_ids.LAST
      LOOP
         UPDATE company SET status = 'C'
          WHERE company_id = company_ids(id_ind);
      END LOOP;
   END;
END;

The problem with this code is that it assumes the company_ids table is filled from first to last row. But the row numbers are company ID numbers, and there is a good chance they are not sequentially defined (at least those companies slotted to be closed).

Consequently, you are always better off using ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

Oracle Database 12c PL/SQL Programming

Oracle Database 12c PL/SQL Programming

Michael McLaughlin
Oracle PL/SQL for DBAs

Oracle PL/SQL for DBAs

Arup Nanda, Steven Feuerstein
Oracle PL/SQL For Dummies

Oracle PL/SQL For Dummies

Michael Rosenblum, Paul Dorsey

Publisher Resources

ISBN: 9781449324070Supplemental ContentErrata Page