A Hybrid Temporal XML Index Model

As the application of XML is used more and more widely, the requirement of XML query is higher and higher. Any query on XML data may cause the traversing of the whole XML document tree,if there is no index structure in XML document. The cost of this traversing may be insupportable for large document. Finding efficient and useful ways to search and index semi-structured XML documents is a popular research topic.Among existing indexes, "ViST is a powerful index. However, when answering a XML path whether exists in XML document, its performance degrades significantly. And the search results may be different form the parts of XML document. In this paper, we address the problems by putting forward a novel index structure, called a Hybrid XML Index Composing Structure-Encoded With Cluster (HiSC for brief). Every path in XML document can be transformed into a sequence of labels by Structure-Encoded that constructs a one-to-one correspondence between XML tree and sequence. Base on identifying characteristics of nodes in XML tree, the elements are classified and clustered. During query proceeding, the twig pattern is also transformed into its Structure-Encoded. By performing subsequence matching on the set of sequences in XML documents, all the occurrences of path in the XML documents are refined. Using the index, the query efficacy is quicken by reducing the access of irrelevant dataset. The search results with pertinent format provide more structure information without any false dismissals or false alarms. The index also supports keyword search. We test the index on XMARKE dataset, which is the standard sample. The experiment results indicate the index has significantly efficiency with high precision.The application of temporal information is coming into every field. Because of the tremendous storage and heterogeneous characteristic, the processing of temporal information is getting more and more multiform and complicated. However, The XML composing temporal technology can process temporal information efficient. In this paper, we present a novel model for temporal XML document. Our approach is based on a temporal data model allowing representing both transaction time and validity time dimensions of XML documents. The temporal XML document is modeled by a temporal by changing XML Schema to accommodate time-vary data. Temporal information is separated into the element of history and current, which can supply more efficient query. And we also describe the way to update the temporal data. The model is proved to satisfy the temporal consistence and the path consistence.