There are unique criteria in DW that differentiate it with database management system (DBMS). DW is a subject
oriented, integrated, time varying and non-volatile collection of data[7]. It contains historical data and those stored
data will not be either deleted or changed. Analyzing historical, summarized and consolidated data could lead to
precious information such as trend and behavioral correlation. The uniqueness of DWs features cause differences in
DW modeling and design. For example in DBMS, redundancy should be eliminated to enhance business process
while in DW the existence of redundancy is required to enhance DW performance. However, keeping all historical
data that had rarely changed is costly since it requires big data space. To encounter this problem, Kimball et al
(2008) proposed slowly changing dimension method to increase its efficiency [9]