Twig Pattern Matching Algorithms for XML

The emergence of XML promised significant advances in B2B integration. This is because users can store or transmit structure data using this highly flexible open standard. An effective well-formed XML document structure helps convert data into useful information that can be processed quickly and efficiently. From this point there is need for efficient processing of queries on XML data in XML databases like XML-enabled (MS-SQL Server, Oracle), Native XML (Mark Logic Server, EMC xDB). The research area in XML database is processing of XML tree pattern query (TPQ) called twig with efficient answers .Generally we have parsers that constructs the parse trees for some representation. Similarly, we have XML DOM parser it converts the XML document into XML tree. The XML query languages like XQL(XML Query Language), XML-QL(a query language for XML), Quilt, XPath (Extensible path language), XQuery (Extensible Query language) represent queries on XML data as twigs(small tree patterns).The major operation of XML query processing is to find all the occurrences of twig patterns efficiently on XML database. In the past few years, many algorithms have been proposed to match such tree patterns (twigs). This paper presents an overview of the state of the art in TPQ processing. This overview shall start by providing some background in holistic approaches to process TPQ and then introduce different algorithms for twig pattern matching.