Foreword – Introduction to Database Management Systems

Forword

Like many technologies in the computer industry, the evolution of databases can be tracked back to research into automating office functions in the 1960s and 1970s. Firms discovered it was becoming far too expensive to hire people to do certain jobs such as storing and indexing files. They began investing in research into cheaper and more efficient mechanical solutions.

In 1970, an IBM researcher named Ted Codd published the first article on relational databases. It outlined an approach that used relational calculus and algebra to allow non-technical users to store and retrieve large amounts of information. Codd envisaged a system where the user would be able to access information stored in tables with “natural language” commands.

The article's significance was not recognised because it was far too technical and relied heavily on mathematics. However, it did lead to IBM starting a research group known as “System R”.

Eventually, System R evolved into SQL/DS which later became DB2. The language created by the System R group, SQL (Structured Query Language) has become the industry standard for relational databases and is now an ISO standard.

The first database systems built upon the SQL standard appeared at the beginning of the 1980s from Oracle with Oracle Version 2, and later SQL/DS from IBM, as well as a host of other systems from other companies.

Relational database technology was continually refined during the 1980s. This was due to feedback from customers, the development of systems for new industries and the increased use of personal computers and distributed systems.

By the middle of the 1980s, it had become obvious that there were several fields where relational databases were not practical due to the types of data they used. These areas included medicine, multimedia and high energy physics and they needed more flexibility in how their data was represented and accessed.

This led to research into object oriented databases where users could define their own methods of access to data and how it was represented and manipulated. This coincided with the introduction of Object Oriented Programming languages such as C++ which started to appear in industry at the same time. Since then, in the late 1990s and the early years of this decade, we have seen huge advances in the technology behind running databases and securing them.

Since their arrival, databases have expanded in size from the 8MB of data that System R had been tested with to terabytes of data used for mailing lists, credit card information for banks and so on. With each increase in the amount of storage available, we have seen a corresponding increase in the size and complexity of database systems in operation.

In today's scenario, databases are ubiquitous in all modern corporations, so much so, that professionals carry smaller databases on palmtops or mobile phones. It will be hard to find any successful organisation that does not deploy databases for their key operations. This subject is now being taught and discussed in primary schools in urban areas. This area of technology has spun off a huge cottage industry around it, spanning from the technical support novice to highly specialised very large database management gurus.

It is in light of this background that Atul's book is very significant. Effective database management has become a critical success factor in corporate IT strategy. Although, there are a number of books on this subject available in the market today, Introduction to Database Management Systems stands out because of the wide range of topics that it covers and the simple and lucid manner in which it explains them. It will be of tremendous value to students of this subject, who can also use it as a reference tool.

While working with Atul over the years, I have always been impressed with his thorough understanding of database management and other related topics. He also has outstanding ability to present his thoughts in the most palatable fashion. I am delighted that he has come out with this book that explains the theory behind database systems, their architectures and issues in a way that even a layman can understand. Atul has put to good use his practical experience while working with us at i-flex, mixed with his very good grasp of theory of databases.

I wish him all the best in his future endeavours.

Deepak Ghaisas

CEO (India Operations)
i-flex Solutions Limited
Pune