Uniform Access Interface Based On The Xmla Standard Data Warehouse Realization

With the development of the database technology and the wide application of the database system,there have been a great deal of history data accumulated in all kind of database system. Online Analysis Processing(short for OLAP) which can find the regulation and refine the useful information from those existing data has been used as the base of enterprise decision-making,and it also emphasized on taking useful information by data analysis based on the DW (Data Warehouse).From another aspect,OLAP,which is an advanced DSS tool,has been more and more popularly used to make deep investigation of business data,find the business tendency and abnomrality,get important details and make better understanding of rules of their business behaviors.However,a majority of OLAP manufacturers have native data access standards instead of uniformed data access standards,therefore, there is a great challenge to the unified access to the data warehouse.In order to achieve the target of uniformly access to heterogeneous data warehouse even realize the integration with them, a majority of OLAP tool manufactures take great efforts to develop the unified OLAP API interface which can access all OLAP server.The necessary to develop unified OLAP API standard which can acesses to all OLAP server can be analyzed from three respects:(1)from the respect of the data warehouse developer, the single tool is rarely able to fully meet the changing needs of the users,and it is also difficult to integrate with various product.(2)from the respect of the data warehouse user, in face of a great deal of data,it can not easily find the really needed information,and it is beyond challenge to completely and correctly express that information.(3)from the respect of the data warehousing vendors,metadata integration is too costly because of lacking of the standard format of the share information.This paper,in the first place.briefly introduces the research status home and abroad along with the related theory of data warehouse,OLAP technology. And then the metadata model of Microsoft Analysis Services.Modrian and Oracle OLAP Server come to understand in order to realize the implementation of the uniformly access to metadata from all kinds of data warehouse.Three standards of access to data warehouse as well as MDX query language is extremely studied.and especially, the XMLA standard and MDX query language is analysised in detail.due to the Oracle OLAP Server does not support the XMLA standard and MDX query language.To achive the target that the realization of uniformly access to data warehouse in accordance with XMLA standard, the mapping between Oracle OLAP metadata model and XMLA data model is firtly implemented.and then the MDX parser which can parse the MDX language based on MDX character must be developed,the overall system architecture is designed in accordance with the above theoretical knowledge.the architecture takes adventage of Brower/Server three-tier structure,front-end presentation layer makes use of the open source JPivot product.which is a custom JSP tag libraries and covers all OLAP functions and operations, especially supporting for accessing the data source via XMLA standard;the control layer takes adventage of the developed engine in accordance with the XMLA standard(short for XMLA Engine);the data layer takes adventage of an Oracle11g database. In the second place, the design and implementation of the Oracle OLAP so as to provide the data source for XMLA Engine.Finally, in order to the realization of the system and test the system, the front-end JPivot can be uniformly access to Oracle OLAP, Microsoft Analysis Services and Mondrian in accordance with the XMLA standard through the XMLA Engine, thus, achieving the target.