Left child and right sibling structural join algorithm based on extended prefix-coding

To implement structural query of XML document more effectively,improve the efficiency of structural join a new structural join algorithm that adopts the extended prefix-code scheme by adding two fields of type and index to locate the nodes of tree in the ancestor list and descendant list is proposed.Subsequently,this algorithm translates the XML document tree into left child and right sibling tree,and then locates the descendant list for the ancestor element by its index of start point and index of end point.Time complexity analysis of the proposed algorithms indicated the algorithm has better performance than existing structural join algorithms.