One of the traits of a good database is that users are not forced to perceive the structure of the data as it is stored in the tables, but are free to perceive the data in ways that are meaningful to them. Today I share an SQL technique that achieves that goal. (No, you can’t do this with logical files.)

Alternate Reality

Before I illustrate the technique, let’s be sure we understand this idea of allowing the user to perceive the data as he wants to. Suppose a table (physical file) of invoices includes the date that an invoice is

A while back I had a problem that appears to be quite common, but just rare enough that it’s a little challenging when it hits you. Often in our roles as database administrators we need to determine various figures, such as how many key values in a table are used up in case we need to extend the field. Or sometimes we just to provide a statistical representation of data. What I needed was to produce a histogram using SQL.

Let’s say you have an array of sample statistics and you want to break them into groups of an arbitrary

For an upcoming hardware upgrade, I recently contacted all of our third-party software vendors to determine if they were going to increase our fees for running their software on a different machine. My mission was to determine: 1) Whether each vendor would charge us for changing hardware; and 2) Would there be an increase in their yearly software maintenance fees? The results were intriguing and an interesting window on the i/OS software world.

The Other Costs of a Hardware Upgrade

Hardware upgrades aren’t just about a new box. You also must ensure that your existing software will run on that