Conclusion - Information Systems Reengineering, Integration and Normalization - page 371

Chapter 10
Conclusion
As computer technologies evolve, it becomes a necessity for companies to upgrade
their information systems. The objective of reengineering is to protect their huge
investments and to maintain their competitive edge. However, information systems
reengineering is a complicated task that requires much expertise and knowledge.
It needs users' input to recover lost semantics inside the existing database system
and/or the existing expert system. It also requires technical expertise to replace
the obsolete information systems with newer systems. Very often, due to lack of
methodologies and expertise, companies choose to redevelop rather than reengineer
when upgrading their information systems. The purpose of this topic is to convince
these companies that reengineering is a more cost effective and feasible solution.
An information system consists of almost all the computer application systems
in a company. The major components of such systems are databases for production
operation, and expert systems for managerial decision-making. The methodologies
discussed in this topic aim to protect the investment that companies have already
put into these systems. The aim is to find methods of reusing these systems with
new technologies and/or to meet new applications. The proposed methodology for
reengineering information systems is twofold: database conversion and/or database
and expert system integration as follows:
Database Conversion Our objective is to replace (convert) traditional record-
based, hierarchical, or network database systems with table-based relational data-
base and then replace the relational database with object-oriented database and XML
database. The justification is that relational database is more user friendly than a
hierarchical database or network database. Similarly, an object-oriented database is
more productive than a relational database. Our technique in converting the data-
base systems is to develop a common data structure for the hierarchical database,
network database, relational database, object-oriented database, and XML database.
The goal is to eliminate the database navigation steps needed in accessing hierarchi-
cal or network databases. This can be accomplished by imposing secondary indices