Enhancing a relational database: Stepwise, bottom-up design.

摘要

Relational databases have gained in popularity over previous methods for many reasons. Users like them for their simplicity. Users and developers appreciate the data independence features of relational systems; details of storage structures and access strategies are left to the database software itself. Finally, relational databases, properly designed, can be easily modified for various new requirements or as a planned ''bottom-up'' design step toward a corporate information system. The enhancement described here consisted of changing a mainframe database containing information about companies to add another customer's information including current company, company address, and historical company data.