Any data structure or constraint that appears in a logical or physical schema and that conveys no information (does not appear in the conceptual schema). Its aim is to increase the performance of the database and of its application programs. Unnormalized tables, redundancies, and artificially split or merged tables are some popular examples
Published in Chapter:
Database Reverse Engineering
Jean-Luc Hainaut (University of Namur, Belgium), Jean Henrard (REVER s.a., Belgium), Didier Roland (REVER s.a., Belgium), Jean-Marc Hick (REVER s.a., Belgium), and Vincent Englebert (University of Namur, Belgium)
Copyright: © 2009
|Pages: 9
DOI: 10.4018/978-1-60566-242-8.ch021
Abstract
Database reverse engineering consists of recovering the abstract descriptions of files and databases of legacy information systems. A legacy information system can be defined as a “data-intensive application, such as [a] business system based on hundreds or thousands of data files (or tables), that significantly resists modifications and changes” (Brodie & Stonebraker, 1995). The objective of database reverse engineering is to recover the logical and conceptual descriptions, or schemas, of the permanent data of a legacy information system, that is, its database, be it implemented as a set of files or through an actual database management system.