A Brief Introduction to the DataBase Structure Manager

by

Progressive Data Systems
P.O. Box 631
Middleton, WI 53562
Phone (608) 836-5075


The DataBase Structure Manager (DBSM) is a data dictionary system
specifically designed to manage Dbase-type relational database systems.
It provides the ability to maintain multiple database data field
specifications and to create database structures according to their
dictionary specifications. It effectively replaces the dBASE III PLUS
CREATE and MODIFY STRUCTURE commands with a more comprehensive and
controlled development process. The database structures may be
created in the dBASE III PLUS/FoxBase or Clipper file format depending
on the database type specified in the configuration settings.

The DataBase Structure Manager also performs maintenance of index file
specifications and creates Clipper-style index files (*.NTX). All data
dictionary information may be reported in the comprehensive, predefined
documentation reports. A DBSM Structure Import Utility is provided
with the DBSM system to automate the process of updating the data
dictionary with database structure information from existing databases.

The DataBase Structure Manager maintains two data dictionaries. One is
the database dictionary where general information regarding each
database is maintained. The other is the data field dictionary where
information concerning all data fields is maintained including the
assignment of a data field to one or more databases.

The process of developing relational database systems is simplified and
controlled by the DataBase Structure Manager. It is simplified by
allowing redundant key data field definitions to be eliminated. For
instance, a VENDORID key data field that occurs in the vendor master
and inventory databases need only be defined once in the data field
dictionary. After the VENDORID data field has been defined, it may
then be assigned to the appropriate databases.

The development process is more controlled because the singular
definition of key data fields ensures consistent definitions in each
database where it occurs. For example, it is not possible to assign a
key data field to some databases with the data field defined as a
numeric data type and assign it to other databases defined as a
character data type. It also helps to ensure the data field name is
the same in each database by encouraging the assignment of existing
data fields rather than requiring that every data field be defined each
time a database structure is defined.

Updating a data field specification that occurs in multiple databases
requires only one data field change in the data dictionary. Once the
data field has been changed, the databases that contain the data field
may be regenerated by selecting them from a point and select window.
Please notice that in this process, there is no need to find all the
databases that use the data field before making the data field change
and the change that is made will be consistent for all related
databases.



The process of eliminating unnecessary data field definitions need not
be restricted to key data fields. Any data fields that are used in the
same manner, for instance zipcode, may be defined once and then
assigned to as many databases as necessary.

The DataBase Structure Manager also provides the capability to document
the database system. The data field dictionary allows maintenance of
more information than the mandatory specifications (ie., data field
name, type, length, and decimals). Each data field may be documented
more fully than the traditional structure maintenance commands allow by
including such information as picture format, default value, low range
value, high range value, a validation procedure name, description, and
an indication as to whether the field is required during data entry.
In addition, databases and the database system in general may be
described in detail using a open-ended text processor. All of the
information maintained may be reported.

The DBSM Structure Import Utility may be used to gather database
structure information into the data dictionaries from existing
databases. This feature is especially useful for anyone who needs to
understand an existing database system. Once the basic database
structure information is imported, the DataBase Structure Manager may
then be used to enter additional information gained through other
sources.



DBSM System Files
-----------------
The DBSM system files are included in three separate archive files.
The file names and contents are as follows:

DBSMInfo.Arc
DBSMInfo.Doc A brief DataBase Structure Manager (DBSM)
system introduction

DBSM_20.Arc
Read_Me.1st Important DBSM usage and startup information
DBSM.Exe DBSM Version 2.0 executable
DBSM.Doc DBSM Version 2.0 documentation

DBSMImp.Arc
DBSMImp.Exe DBSM Structure Import Utility executable
DBSMImp.Doc DBSM Structure Import Utility documentation



Trademark Acknowledgements
--------------------------
CLIPPER is a trademark of Nantucket Corporation.
dBASE, dBASE III, dBASE III PLUS are trademarks of Ashton-Tate, Inc.
FoxBase is a registered trademark of Fox Software, Inc.