DISTRIBUTED DATABASE SYSTEM

By

M. AHMAD MAHMOOD

Database

A database is a collection of information that is organized so that it can be easily accessed, managed and updated.

Data is organized into rows, columns and tables, and it is indexed to make it easier to find relevant information.

Data gets updated, expanded and deleted as new information is added. Databases process workloads to create and update themselves, querying the data they contain and running applications against it.

Database Management System (DBMS)

A database management system (DBMS) is system software for creating and managing databases.

The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.

Types of Data Base

There are three types Data Base Systems:1. Centralized Data Base System.2. Distributed Data Base System.3. Decentralized Data Base System.

Centralized database

A centralized database holds all data on a central computer such as a mainframecomputer or server.

Distributed Database

A distributed database is a database in which portions of the database are stored onmultiple computers within a network.

Decentralized Database

The user would have to connect to the network and they will have access to thesite that is connected to the user’s computer.

Advantages of DDBS

Reliability, if one of the sites crashes, the system will keep running with the other sites.

Speed, it is faster because the information is distribute and not packed as a whole. Open system, the system could connect to other networks to make it bigger and

accessible everywhere.

Disadvantages of DDBS

Open system, the system could connect to other networks to make it bigger and accessible everywhere.

Proper hardware and software, the database needs proper hardware and software to runproperly, this is expensive to get.

Troubleshooting, there might be connection error that could affect the use of the database by other users.

Basic Differences b/w Databases

Decentralized DatabaseDistributed DatabaseCentralized Database

Centralized database have a central computer.

The distributed database has several central computers.

Decentralized database are separated and have different central computers.