Techniques for partial rewrite of XPath queries in a relational database
US7386568B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 8, 2004 |
| Grant date | Jun 10, 2008 |
| Priority date | — |
| Expiry date | Jun 11, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99943
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Techniques are described for executing queries that have XPath sections that specify unmappable paths. The techniques involve splitting the unmappable paths into (1) a mappable path fragment, and (2) an unmappable path fragment. After an unmappable path has been split into a mappable path fragment and an unmappable path fragment, the XPath section is replaced with a replacement XPath section. The replacement XPath section specifies two operations: a “mappable operation” that is based on the mappable path fragment, and an “unmappable operation” that is based on the unmappable path fragment. The portion of the replacement XPath section that specifies the mappable operation is rewritten to access underlying relational structures. Consequently, when the rewritten query is executed, a smaller amount of XML data needs to be materialized to evaluate the unmappable path fragment than would otherwise have been required to evaluate the original unmappable path.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.