Design and implementation of query rewriting system based on materialized views

With the emergence of mass XML documents,how to effectively manage and query XML data has become a problem which should be solved immediately.To store and query XML documents in relational database by the materialized view and query rewriting technologies is studied in combination with the needs of database development.The technology of query rewriting based on Materialized View is an important technology in query optimization field.To answer a new query by using cache view result without accessing to any source database can save time of the query processing.Based on the research of materialized view,view cache and query rewriting technologies,how to use the materialized view which is cached in relational database to answer query is discussed.A prototype of XML data query system based on materialized view was achieved.The extended pattern matching algorithm is adopted in the system to realize the pattern matching of multi-branch route and make sure if the rewiting is existing.The matching result gotten by pattern matching algorithm is used to determine whether the compensation expression can be constructed.The results of rewriting can be obtained through the algorithm of constructing the compensation expression.The query is completed through views cached in the database.