XVII
CHANGES TO THE NINTH EDITION
In this ninth edition, we have added some new features and we have reorganized some of the coverage to provide a
better flow of material. Aside from enhancing the already strong database design coverage, we have made other
improvements in the topical coverage. Here are a few of the highlights:
• Updated Business Vignettes showing the impact of database technologies in the real world.
• Strengthened the database design contents by more clearly differentiating among the conceptual, logi-
cal, and physical design stages.
• Streamlined and modernized the coverage of database evolution and the importance of database design
skills.
• Enhanced the coverage of data models by shifting the focus from a historical perspective to emerging
data technologies.
• Expanded end-of-chapter review questions and problems and introduced a new Cases section to
selected chapters.
• Formalized and improved consistency of normalization concepts.
• Improved readability and overall visual appeal of the book.
• Created a database design process guide and a data modeling checklist as cover inserts.
This ninth edition continues to provide a solid and practical foundation for the design, implementation, and manage-
ment of database systems. This foundation is built on the notion that, while databases are very practical things, their
successful creation depends on understanding the important concepts that define them. It’s not easy to come up with
the proper mix of theory and practice, but we are grateful that the previously mentioned feedback suggests that we
largely succeeded in our quest to maintain the proper balance.
THE APPROACH: A CONTINUED EMPHASIS ON DESIGN
As the title suggests, Database Systems: Design, Implementation, and Management covers three broad aspects of
database systems. However, for several important reasons, special attention is given to database design.
• The availability of excellent database software enables even database-inexperienced people to create
databases and database applications. Unfortunately, the “create without design” approach usually
paves the road to any number of database disasters. In our experience, many, if not most, database sys-
tem failures are traceable to poor design and cannot be solved with the help of even the best program-
mers and managers. Nor is better DBMS software likely to overcome problems created or magnified by
poor design. Using an analogy, even the best bricklayers and carpenters can’t create a good building
from a bad blueprint.
• Most of the vexing database system management problems seem to be triggered by poorly designed data-
bases. It hardly seems worthwhile to use scarce resources to develop excellent and extensive database sys-
tem management skills in order to exercise them on crises induced by poorly designed databases.
• Design provides an excellent means of communication. Clients are more likely to get what they need
when database system design is approached carefully and thoughtfully. In fact, clients may discover
how their organizations really function once a good database design is completed.
PREFACE