XML Structural Join Algorithm Based on Extended Region Coding

The efficiency of structural join directly influences the function of the XML query.The classical Anc-Des-B+algorithm's ability of skipping the descendant codes(not child) is not effective when judging the parent/child relationships.Based on the idea of extended region coding,this paper puts forward a kind of improved method which codes every node into a group of 6 elements including the parent's information.It also puts forward the ZParent algorithm which can skip all nodes that don't participate in join and can carry out join calculation with only one time to scan the P list and C list.Experimental result shows that the method has better time function.