Techniques for efficiently storing and querying in a relational database, XML documents conforming to schemas that contain cyclic constructs

US7523131B2 · kind B2 · utility

Assignee

• Oracle International Corporation · US

Inventors

• James Warner · Mountain View, US
• Abhyudaya Agrawal · San Francisco, US
• Hui Zhang · Fremont, US
• Muralidhar Krishnaprasad · Fremont, US
• Ravi Murthy · Fremont, US
• Zhen Hua Liu · San Mateo, US
• Nipun Agarwal · Santa Clara, US
• Vikas Arora · Ottawa, CA
• Susan Kotsovolos · Belmont, US
• Anand Manikutty · Foster City, US
• Rohan Angrish · Redwood City, US

Key dates

• Filing date: Feb 10, 2005
• Grant date: Apr 21, 2009
• Expiry date: Jan 5, 2026

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S707/99943
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

To associate XML data objects (“child objects”), stored in rows of relational or object-relational tables, with the appropriate XML data objects (“parent objects”) from which the child objects descend, tables that contain child objects (“out-of-line” tables) are constructed with an additional column. In one embodiment, this column stores values that identify the root objects, in the appropriate table, from which the respective child objects descend. Hence, the root object from which any given object descends is traceable by following the respective value back to the corresponding root object. In one embodiment, this column stores values that identify the complete XML hierarchical path, through multiple tables, back to the root object from which the respective child objects descend. Consequently, XML query language queries against XML documents stored in such tables can be rewritten as SQL queries against the data in the tables, even in the presence of cyclic constructs.