Tip Bank

DevX

Finding the Most Recent and Consecutive Data

Question: [Joe Celko’s Pension Plan Puzzle]Luke Tymowski, a Canadian programmer, posted an interesting problem on the MSAccess forum on CompuServe in 1994 November. He was working on a pension fund

DevX

What does AFX stand for?

Question: I see the term “AFX” everywhere in the MFC source code.For example, “AFX_MSG_MAP”. What does it mean? Answer: I once asked this of Jeff Harbers, one of the original

DevX

Calculating Averages Using Clock Times

Question: Joe Celko’s Store Survey Puzzle]You are collecting statistical information stored by the quarter hour. What your customer wants is to get information by hour ? not on the hour.

DevX

What is GMD’s Dynamic Worlds proposal about?

Question: Please explain Dynamic Worlds. Answer: “The Power of Dynamic Worlds” proposal from the German National Research Center (GMD) is based on an interaction model developed for collaborative distributed virtual

DevX

Nested Outer Joins

Question: [Joe Celko’s Outer (JOIN) Limits Puzzle]Gerard Manko at ARI had a problem in 1994 April. They had just switched over from Paradox to Watcom SQL. The conversion of the

DevX

Comparing Aggregate Results

Question: [Joe Celko’s Promo Puzzle]Let’s assume that you have just gotten a job as the sales manager for a department store. Your database has the following two tables. One is

DevX

How can I create VRML pages?

Question: What can I use to produce VRML, or can I write it like HTML? Answer: It is possible to write VRML as a purely text-based language, using a regular