Science and Development Network (SciDev.Net)
An efficient functionality of any distributed database system "DDBS" is highly dependent on its proper design in terms of the adopted fragmentation and allocation methods. However, an optimal fragmentation and allocation design techniques could be very complex and requires good experiences and knowledge to reach. Fragmentation of a large, global databases are performed by dividing the database relations horizontally, vertically or as a combination of both. In order to enable distributed database systems to work efficiently, these fragments have to be allocated across the available sites in such a way that reduces communication cost i.e. to minimize the total volume of data transmitted during queries execution over sites.