CS712 Official Handouts

Introduction:

This is an advanced course of the previous that you must have previously studied and that is the “Database Management Systems”. This course enhances the concepts learnt earlier, moreover, the applications where you will be applying the concepts and the techniques learnt in this course are also more advanced and complex by nature. The Distributed Database Management Systems (DDBMS) uses the concepts of:

1. Database Management Systems
2. Networking

The key is to identify the environments in which we have to use the distributed databases. You may realize that using distributed databases in some situations may not prove to be fruitful. The implementation may develop drawbacks or may become in-efficient.

As a computer or database expert, you will always be having the basic assignment that you are given a system for which you have to design/develop a solution or a database system. You will have several options available and interesting thing is that every one of them would work. Now the challenge lies in selecting the most feasible solution. For this, the merits and demerits of every approach have to be analyzed. If this evaluation is not properly done in the beginning then it is very difficult to apply adjustments in the later stages. To be more precise, Distributed Database System (DDBS) will be one of many options available to you for any system that you will be asked to develop. It is your job to analyze whether the environment needs a DDBS solution or any other one. A wrong decision in this regard may introduce inefficiency rather than any advantage.

Note:

Lack of experience or/and homework may lead to the selection of a wrong option

Outline of Course

There are going to be four major component in this course:

Introductory Stuff Architectures and Design Issues Technological Treatment Related Topics

Introduction:

This part will cover the introduction to the basic concepts of databases and networks. Then we will also realize the nature of application that need a DDBS, so that we are convinced that this is the environment and it requires a DDBS and then we think and plan the later issues of the implementation.

Architecture and Design:

There are different architectures available for designing distributed systems and we have to identify the right one as different architectures are suitable for different environments. Moreover, there are different approaches to implement the DDBS designs, we will study those approaches since each suits different environment.

Note:

Selection of wrong architecture in an environment results in an in-efficient system

Technological Treatment:

Different design approaches of DDBS will be implemented using the prevailing DDBMSs, like SQL Server and Oracle. That will give you the idea of how a real DDBS will look like.

Theoretical Aspects:

We will discuss the theoretical aspects related to the DDBS. The study of these issues will help you administering a DDBS on one side and on the other side it will help you in the further studies/research in the DDBS. The database management systems available today do most of the administration automatically but it is important for the database designer to know the background procedures so that the overall efficiency of the distributed database management systems may be enhanced.

Recommended Books:

1Distributed Database Systems (2nd Edition) by T.M., Ozsu, P. Valdusiez 2- Distributed Database Systems. By D. Bell, J. Grimson, Addison-Wesley, 1992 3- Distributed Systems: Concepts and Design, 4th Edition, by G. Coulouris, J. Dollimore, T. Kindberg, Addison-Wesley

The book mentioned at No. 1 is the main book for this course. It is a famous and one of the rare books written on the topic. Course is mainly based on this book. So you will holding this piece very frequent in coming days, make it a bedside item.

You are already familiar with the marks split, that consists of mid-term exam, assignments and a final exam. Good luck with your course and now lets start reading.

History:

This part is from the first course of Databases. Computer applications are divided into two types:

1. Data Processing Applications
2. Scientific / Engineering Applications

Data Processing Applications in computer terminology are referred to as “File Processing Systems”. In those applications the data was processed with the help of different programming languages. The program, which was used to process the data, had the data defined in it, therefore they were dependant on each other. If we had to make any change in the program it was difficult, as we had to take care of the dependant data as well and vice versa. You are already familiar with the following diagram

Examination · Registration · Library · Library · Examination · Registration Applications · Applications · Applications · Library · Examination · Registratio Data · Data · n · Files · Files · Data · Program and Data Interdependence · Typical File Processing Environment

For example in the above example we can see three systems i.e. Examination, Library and the Registration system. Each of them is having its own data for processing, however there might be some information which is common to all the three systems but still being stored separately. This results in:

1. Data Redundancy
2. Expensive Changes/Modifications due to redundancy of the data