Efficient way to evaluate aggregations on XML data using path-based row sources
US8301620B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 2009 |
| Grant date | Oct 30, 2012 |
| Priority date | — |
| Expiry date | Apr 14, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/8365
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The approaches described herein provide an efficient way for a database server to process certain kinds of queries that require the evaluation of an aggregation function over XML data stored in an object-relational database. An aggregation function takes multiple inputs and generates a single output. A database server first determines whether the query qualifies for this particular kind of optimization, then creates a query execution plan that specifies the use of an enhanced path-based row source, eliminating the need for a second path-based row source for computing the aggregation function. The enhanced path-based row source specified in the query execution plan computes an aggregation function and stores the result of that function computation in a column of each row. The XPath evaluation results that are the individual inputs to the aggregation function are only stored temporarily until they are used to compute the aggregation function.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.