Query Decomposition Algorithm Based on Multi-source Heterogeneous Data

In order to solve the problem that global query can not query heterogeneous data sources,this paper proposes to decompose the global query into sub-queries against heterogeneous data.It designs query decomposition and subquery reconstruction algorithm.Query decomposition is based on JavaCC and JJTree to abstract the global query into a syntax tree.Subquery reconstruction algorithm traversals the syntax tree,chooses different reconstruction algorithms based on the current node type,and constructs the sunquery based on different datasource.