APPLE

Data Management
by Malcolm Slovin
M
anaging your data is not the easy task many software
vendors would have you believe. Software ads for
"database" systems attempt to impress you with their
easy data entry methods, fast sorting and searching routines
and flexible reporting formats. These ads conjure up visions of
days of leisure while your new computerized filing system
works unceasingly (and certainly flawlessly) to keep your
business organized and profitable. In point of fact, much
thought, effort and learning are required before a "database"
system will perform as an integrated part of your business.
What we'll do here is to begin exploration of the area of
"database" systems, and provide information and examples
on choosing and using these software systems in your
business. As a first step it is important to understand what a
"database" system is and a bit of how they work In future
articles I hope to provide some reviews of current software and
world business examples of their use and abuse.
Much of this information is derived from the activities of the
International Apple Core's Data Management Special Interest
Group, a group which concentrates on the various software
packages available for filing systems, data base systems and
possibly, data analysis systems. The SIG' s interest is not only in
what these packages are capable of doing but also in how they
accomplish the data management task This includes factors
such as storage device formatting, virtual memory usage,
types of storage files created and print facilities.
As a starting point let's divide a computer system into two
areas: the computer itself, and the storage devices. Systems
software (in whatever form) controls the movement and
interaction of data within and between both areas. At this level
we are concerned with the management of data by those
utilities and programs that directly control the operation of the
computer system. It is therefore important to look closely both
at operating systems and data management utlilities.
What's a Database?
The term "database" has been used to cover everything
from simple filing systems to program generators. In a simple
filing system, data items are stored in records and the records
are stored in some organized fashion in a file. This is similar to
the common filing cabinet kept by most homes and businesses.
One file cabinet might contain all of the information about each
of our customers, and each paper file folder would represent an
individual customer. The information in each customer's
folder represents data items which are usually entered next to
the appropriate field name in the folder. The name of John Doe
appears in the NAME field and his address appears in the
ADDRESS field. (He also happens to manufacture Widgets
which appears in the PRODUCT TYPE field).
In a computer filing system of this type, one made up of
similar or the same types of records, the records form a flat file
or data file. Programs are then written to allow you to access
these records, and the data items they contain, so that you can
add, update (or change), delete and report on the information
contained in the filing system. In the" good old days" (five to ten
years ago) programs were written specifically to access that
particular file and its contents. If you developed a new file then a
new set of programs had to be written to perform the same set
of functions for this new set of information.
Fortunately, programmers got tired of "re-inventing the
wheel". This gave rise to the type of filing system available
today. A set of programs are developed, each of which
performs a specific function such as Add Data to The Record,
Delete Data, Add A Record, Delete A Record, etc. These
"routines" can be used to access information contained in
several different files, although only one file can be accessed at
a time. If you want to add data to your Customer file you must
first finish with your Accounts Due file and put it away before
opening your Customer file. You cannot easily combine data
from both of these files for report, nor can you update both files
simultaneously even if they both contain some of the same
information.
Although the " routines" approach may seem superior to the
specific program approach, you still lose something. A pro·
gram written specifically for your application is a customized
piece of software and as such can provide records tailored to
your exact needs in an extremely efficient manner. However,
routines cannot be easily customized. In essence, you may
have to tailor your business requirements to the systems
requirements if you want to use that software. For example, you
may have a small paragraph which summarizes your customer's
past dealings with you. In the custom system these paragraphs
could be of any length while in the "routines" system there may
be a requirement that no field (in this case the one called PAST
DEALINGS) have a length greater than 256 characters. If you
couldn't describe your customer's past history in 256 charac·
ters or less you'd be out of luck (and room).
Most of the systems on the market today are variations on
the "routines" type of filing system, although for obvious
reasons many businesses are going back to having custom
systems developed forthem (just like in the old days). lfyou can
use a simple filing system it is important that you determine the
limitations of the system before you purchase it so that it meets
most or all of your needs. Don't trust the package blurb to "tell it
44 Apple Orchard