Analysis of Joins and Semi-joins in Centralized and Distributed Database Queries

Database is defined as collection of files or table, where as DBMS stands for Database Management System which is collection of unified programs used to manage overall activities of the database. The two dominant approaches used for storing and managing database are centralized database management system and distributed database management system in which data is placed at central location and distributed over several locations respectively. Independent of the database approach used, one of the foremost issue in the database is the retrieval of data by using multiple table from central repository in centralized database and from number of sites in distributed database. Joins and semi joins are primitive operations used to extract required information from one, two or multiple tables. In this paper the focus is given on computing and analyzing the performance of joins and semi joins in centralized as well as in distributed database system. The various metrics that will be considered while analyzing performance of join and semi join in centralized database and distributed database system are Query Cost, Memory used, CPU Cost, Input Output Cost, Sort Operations, Data Transmission, Total Time and Response Time. In short the intention of this study is compare and contrasts the behavior join and semi-join approach in centralized and distributed database system.