IMAGE's coming of age


Breaking free from restrictions to Database transformations

F. Alfredo Rego
Profesor del Instituto de Informática y Ciencias de Computación
Universidad Francisco Marroquín
Ciudad de Guatemala, Guatemala



The original research report was presented by the founder of Adager Corporation during the 1978 HP3000 International Conference in Denver. Some of the terminology has evolved through the decades, but the fundamental ideas are timeless. In 1988, after 10 years in Guatemala, Adager Corporation moved its operations to Sun Valley, Idaho, USA


www.adager.com

Abstract

A computerized database should reflect an organization's way of behaving. As real-world circumstances change — forcing the organization to adopt new ways and abandon old ones — the database should also adapt itself. This is easier said than done.

Hewlett-Packard provides tools, such as DBUNLOAD and DBLOAD, which allow a limited set of transformations to IMAGE/3000 databases. But these tools do not lend themselves to the easy implementation of the radical transformations that are sometimes necessary. The restrictions of these tools, we feel, are analogous to the restrictions imposed on children by loving parents.

Taking into consideration that children (just like computer users) eventually come of age and will do their own thing despite formidable obstacles, we have developed a software system called DATABASE.UTILITY to help IMAGE/3000 users out of their database transformation predicaments.


Buzzword-compliant editorial notes (written 21 years after the article's publication in 1978)

We shall use the term "Adager" (coined in 1979) instead of DATABASE.UTILITY. Adager means The Adapter/Manager for IMAGE/3000 Databases.

This article reflects the state of the art in 1978. Computers have changed dramatically since then and, as Hewlett-Packard evolved IMAGE/3000 into TurboIMAGE and IMAGE/SQL, Adager changed accordingly. The few "functions" described in this paper have grown immensely and their names have also become less cryptic ("PAVEPATH" became "Repack Dataset" and "CAPDTAIL/CAPMASTR" became "Change Capacity").

With the Internet, the HP3000 has become a powerful web server that can support millions of transactions based on IMAGE databases — on a daily basis and with thousands of concurrent users who can be anywhere in the world. As a result, the HP3000 is known as HP's Enterprise Database Server for Business-Critical Computing.

The performance of IMAGE/SQL databases has benefitted from improvements in computer hardware, as 16-bit CISC gave way to 32-bit RISC in the mid 1980s. For the new millennium, Hewlett-Packard is taking the HP3000 into 64-bit hardware architectures pioneered by HP in conjunction with Intel.

This article, however, is about the state of the database art in 1978. So, please rewind your calendar for this flashback. The only difference is that we now have to worry about terabytes instead of megabytes and about doing, in one thousandth of the time, what we could do leisurely back in the 1970s.


Motivation for the development of Adager

How can I be sure that my database design is perfect? How can I guarantee that I will never have to change my database to meet unexpected shifts in my organization's way of doing things?

If I can not answer these questions to my satisfaction, then what type of tuning (and fine-tuning) tools do I need to facilitate the constant and inevitable evolution of my database?

What worries me about the tools I have currently available to me? What type of questions linger in my mind as I dream of better and more effective ways to do what I have to do anyway?


Description of Adager

Adager is a suite of programs designed specifically to allow a large selection of transformations to IMAGE/3000 databases without having to mess around with magnetic tapes or schema recompilations.

Adager invests a good 90% of its time making reasonably sure that your requested transformations are legal and will not produce unpleasant results. Strict log-on subsystems verify that only authorized users access a database.

All of our design trade-offs have one main objective: to preserve database consistency and integrity. At the least sign of trouble, Adager does its best to back out and to salvage the original database.

When necessary, the RootFile is appropriately updated; MPE files are created or purged as needed; datasets are reorganized to include or exclude structural information; datasets and data items are renumbered if any intermediate elements have been eliminated, etc. You don't have to worry about the myriad details involved in even the simplest database transformation, because Adager automatically takes care of all the overhead.


Global database transformations


Transformations of detail datasets


Transformations of master datasets


Transformations of data items


Transformations of element references


Transformations of access paths


Conclusion

Adager keeps track of all IMAGE/3000 internal housekeeping, while your database evolves.

You are now free to concentrate your attention on the only housekeeping task that really matters: Your database's accurate reflection of your organization's way of doing business.

You can now specify — without fear — whatever you need in your database today, according to today's requirements. Tomorrow, you can easily remodel your database according to the constantly changing conditions of your business.

Thanks to Adager, The Adapter/Manager for IMAGE/3000 Databases, you have broken free from restrictions to database transformations.



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