Monday, December 29, 2003		Book Review

DATABASES, an essential part of any organisation, are used for maintaining internal records and for other commercial purposes. Database is nothing more than a collection of information that exists over a long period of time. To access information from a database, you need a database management system (DBMS). A DBMS is a powerful tool for creating and managing large amounts of data efficiently. Some commercially available database management systems are Foxpro, Access, Oracle, Ingres and Sybase.

The book under review has been written by three well-known computer scientists from Stanford University. Before making use of this book you should have some knowledge of data structures, software systems and programming languages. The book has been written in easy-to-understand language and provides with real world examples in each chapter.

The first half of the book provides in-depth coverage of databases from the point of view of the database designer, user and application programmer. The details about various database models have been given in the earlier chapters. The models discussed include Entity-Relationship Data Model (E/R Model) and Relational Data Model. The Entity Relationship Model is graphical in nature, with boxes and arrows representing the essential data elements and their connections.

The latest database standards covered in this part includes SQL-1999, SQL/PSM, SQL/CLI, JDBC, ODL, and XML, with broader coverage of SQL. SQL (Structured Query Language) is the principal query language for relational database systems. The extensive coverage of query processing and query optimisation, supported by an extended relational algebra which is designed to match the real features of SQL has been provided in this part.

The second half of the book provides in-depth coverage of databases from the point of view of the DBMS implementer. It focuses on management, covering the principal techniques in these areas with broader coverage of query optimisation than other texts. It also covers information integration, including warehousing, mediators, OLAP, data cubes and data-mining techniques.

The chapter on Data storage explains the devices used to store huge amounts of information, especially rotating disks. For the recovery of data in case of disk crashes, the concept of RAID (Redundant Array of Independent Disks) has been explained. Many important specialised topics, such as error-correction in RAID disks, bitmap indexes, concurrency control, use of data statistics has been explained in this part.

Advanced topics that includes multidimensional and bitmap indexes, distributed transactions, and information integration techniques has been discussed in detail.