100 results about "XQuery" patented technology

A message broker can allow any server in a cluster to publish to, and subscribe, to a message channel. A server subscribing to a channel can set up a message filter such that XQuery expressions can be used to filter against the messages arriving on the channel A message broker can also utilize a unique filtering algorithm to optimize data access. Static subscription information can be captured in order for a message broker to do client-side filtering. A message broker can also construct and maintain at least one table in memory that indicates whether any server in the cluster may ever do a dynamic subscription. For dynamic subscriptions, the publishing server can extract the information from a database, such as by executing a DBMS select on a subscription table using a primary key lookup.

This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

The invention discloses an XQuery-based query engine system comprising a mediator and a wrapper. The mediator comprises a lexical analysis module, a grammar analysis module, a normalization module, aquery decomposition module and a result processing module, wherein the lexical analysis module breaks the XQuery statement into a token carrying an attribute; the grammar analysis module organizes thetoken into an abstract syntax tree based on an XQuery grammar specification; the normalization module arranges the syntax tree to form a well-formed syntax tree; the query decomposition module traverses the syntax tree, generates a subquery with respect to an underlaying data source and transfers corresponding wrappers; and the result processing module receives a query result transmitted by the wrapper and returns the query result to a user in the form of XML. The wrapper comprises a relation-type data source wrapper and an XML data source wrapper, and receives the XQuery subquery which is transmitted from the mediator and converted into query language supported by the data source for underlaying data source query, and the final result is reconstructed into XML format and transmitted to the result processing module. The invention improves the query efficiency, ensures favorable structure of the query clause constructed by normalization of the abstract syntax tree and enhances the readability.