Pre-Grant Publication Number: 20090125495
Filing Date: November 09, 2007
Inventors: Ning Zhang, Sivasankaran Chandrasekar, Nipun Agarwal, Sam Idicula
Assignee(s): Oracle International Corporation
Current U.S. Classification: 707, 707/004000, 707/E17001
Abstract

A database system may perform a streaming evaluation of an XPath expression by utilizing an XPath evaluation component in tandem with an XML event-streaming component. For a more optimal filtered streaming evaluation, the XML event-streaming component may provide an interface whereby the evaluation component sends certain criteria to the event-streaming component when requesting an XML event. The criteria may be based on a next unmatched step in the XPath expression. In response to the request for an XML event, the event-streaming component may only return events that match the criteria. The evaluation component may be, for example, a compiled state machine for the XPath expression. The criteria may be pre-compiled for each possible state in the state machine. The event-streaming component may also utilize the criteria along with schema information to skip parsing of certain segments of XML data.