Research On Query Rewriting In Heterogeneous Data Source Integration System

With the rapid development and wide application of computer technology,the amount of data has been unable to use the "much" to describe,because of the different needs of the data,the data storage mode,data structure and other aspects are different.Therefore,a large number of heterogeneous data sources are formed.But this is not what they want for users,users usually want to be able to get the needed data by submit a query.Heterogeneous data integration system arises at the historic moment.Query rewriting plays an important role in heterogeneous data source integration system.The integration system is to rewriting the query statement given by the user based on the global schema by the query rewriting technology,in order to get the result from the heterogeneous data source and feedback to the user.Query rewriting technology and data integration,query optimization and other issues are closely related.The following research is done on the problem of rewriting of queries in heterogeneous data source integration systems.First of all,the research of the classical query rewriting algorithm,Bucket algorithm,Inverse-Rules algorithm,and MiniCon algorithm are studied in depth,and the shortcomings of the above three algorithms are proposed respectively.This paper focuses on the study of the MiniCon algorithm,and on the basis of the algorithm proposed an improved algorithm,which is based on path optimization MiniCon algorithm.The algorithm is based on the traditional MiniCon algorithm,optimize the step path,by comparing the query field data in view of query efficiency,path optimization,in order to achieve the purpose of improving the efficiency of query.Secondly,this paper introduces three kinds of traditional data integration scheme,namely federated database method,middleware method and data warehouse method.Based on the middleware architecture and the integration of JSON technology,a heterogeneous data source integration framework is designed,which adopts a stable three-layer structure,including the display layer,the middle layer and the data source layer.The middle layer is the system Core,query generation,query rewrite in the middleware layer to achieve.At the end of this paper,the traditional MiniCon algorithm and the improved path optimization MiniCon algorithm are applied to the heterogeneous data source integration system of the above design,and the query rate of the two algorithms is carried out by using the data of Henan Century Mart.The comparison to prove the improvement of the integrity and superiority of the algorithm.