Method and apparatus for XML query evaluation using early-outs and multiple passes
US7716210B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 2006 |
| Grant date | May 11, 2010 |
| Priority date | — |
| Expiry date | Jul 29, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/8365
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus is disclosed for XML query evaluation using early-outs and multiple passes to evaluate an XML query. A multi-pass evaluation procedure evaluates the XML query one step at a time as needed to complete evaluation. The multi-pass evaluation procedure evaluates XML queries containing logical expressions such as “AND” expressions, “OR” expressions, and implied “AND” expressions within “FOR” clauses. Queries containing logical expressions are often satisfied before every component is evaluated. Thus, executing the multi-pass evaluation procedure allows the evaluation to exit early when the veracity of the query is determined, not necessarily when every component has been evaluated. The multi-pass evaluation procedure executes as long as a descendant axis of the XML query need not be evaluated past a child node. When evaluation of a descendant axis past a child node is required, the multi-pass evaluation procedure may switch to a single-pass evaluation procedure to complete evaluation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.