Advantages And Disadvantages Of Distributed Database Systems

DISTRIBUTED DATABASES AND DISTRIBUTED DATABASE MANAGEMENT SYSTEMS

1. INTRODUCTION

Distributed database systems (SBDD) are two approaches to meeting the data processing which may seem diametrically opposed: technology systems and the database of computer networks. Database systems have evolved from data processing in which each application to define and maintain their own data, to one in which the data are defined and managed centrally. This new orientation leads to independent data, such applications become immune to changes in physical or logical data organization and vice versa. A major motivation in using database systems is the integration of data and provide a centralized and controlled access to data. On the other hand, the technology

In a distributed database, data can be stored in different systems like personal computers, servers, mainframes, etc. ii. A user doesn’t know where the data is located physically. Database presents the data to the user as if it were located locally. iii. Database can be accessed over different networks. iv. Data can be joined and updated from different tables which are located on different machines.

v. Even if a system fails the integrity of the distributed database is maintained. vi. A distributed database is secure.

2.2 Disadvantages of distributed database

i. Since the data is accessed from a remote system, performance is reduced. ii. Static SQL cannot be used. iii. Network traffic is increased in a distributed database. iv. Database optimization is difficult in a distributed database.

v. Different data formats are used in different systems. vi. Different DBMS products are used in different systems which increases in complexity of the

The DDBMS synchronizes all the data periodically, and in cases where multiple users must access the same data, ensures that updates and deletes performed on the data at one location will be automatically reflected in the data stored elsewhere. In Addition, the users and administrators of a distributed system, should, with proper implementation, interact with the system as if the system was centralized. This transparency allows for the functionality desired in such a structured system without special programming requirements, allowing for any number of local and/or remote tables to be accessed at a given time across the network.

5.1 Advantages of DDBM's

• Reflects organizational structure

• Improved share ability, availability, reliability and performance.

• Data are located nearest the greatest demand site and are dispersed to match business requirements.

• Faster Data Access because users only work with a locally stored subset of the data.

• Faster data processing because the data is processed at several different sites.

• Growth Facilitation: New sites can be added without compromising the operations of other sites.

• Improved communications because local sites are smaller and closer to