¡¡	Chinese Journal of Computers   Full Text
Title	Research on OLAP System Supporting What-if Analysis
Authors	WANG Shan1),2) XIAO Yan-Qin1),2),3) ZHANG Yan-Song1),2),4) CHEN Hong1),2)
Address	1)(Key Laboratory of Data Engineering and Knowledge Engineering of Ministry of Education, Renmin University of China, Beijing 100872) 2)(School of Information, Renmin University of China, Beijing 100872) 3)(Computer Center, Hebei University, Baoding, Hebei 071002) 4)(Department of Computer Science, Harbin Finance College, Harbin, Heilongjiang 150030)
Year	2008
Issue	No.9(1573¡ª1587)
Abstract &   Background	Abstract Data Warehouse and On-Line Analysiscal Processing(OLAP) are the key components of Decision Support System (DSS). What-if analysis focuses on analysis on hypothetical scenarios based on historical data. It is an important type of DSS analytical processing procedure, and can provide important predicting information for DSS users. This paper firstly surveys major related work of what-if analysis and then briefly discusses the classifications from different angles. The main contribution of this paper is to present the global classification of what-if analysis. Three classical prototypes of what-if analysis based on rules, what-if analysis based on delta table and what-if analysis based on incremental CUBE maintaining are analyzed. Also the advantage and disadvantage of different type of what-if analysis and applying boundary are discussed. The authors¡® recent research work of delta table based on Main-Memory Database and a new CUBE maintain algorithm are discussed to discovery new algorithms on advanced Main-Memory Database architecture. Finally the future work of what-if analysis is summarized. Keywords data warehouse; OLAP; what-if analysis; CUBE; delta table Background What-if analysis focuses on analysis on hypothetical scenarios based on historical data, and it is an important type of DSS analytical processing procedure. In the traditional researches, different prototypes and solutions aimed at specific requirements and scenarios, no complete and global solutions can meet the general requirement of what-if analysis. In this paper, the authors present a framework of what-if analysis which is essential for the future research work, also develop several what-if analysis solutions to fill the gap in the framework. Improving the performance of what-if analysis by the character of main memory OLAP is one of key problems of the study. The work is supported by the National Natural Science Foundation of China(grant Nosª±60473069£¬60496325), the joint research of HP Labs China and Information School of Renmin University, and the joint research of Beijing Municipal Commission of Education. The target of research is to establish a Main-Memory OLAP system based on what-if analysis which can provide high performance and powerful what-if analysis function.