Tree signatures for XML querying and navigation

In order to accelerate execution of various matching and navigation operations on collections of XML documents, new indexing structure, based on tree signatures, is proposed. We show that XML tree structures can be efficiently represented as ordered sequences of preorder and postorder ranks, on which extended string matching techniques can easily solve the tree matching problem. We also show how to apply tree signatures in query processing and demonstrate that a speedup of up to one order of magnitude can be achieved over the containment join strategy. Other alternatives of using the tree signatures in intelligent XML searching are outlined in the conclusions.