Query transformation for queries involving correlated subqueries having correlation join predicates with local filtering predicates involving predicate transitive closure and predicate pull-out
US7181446B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 23, 2004 |
| Grant date | Feb 20, 2007 |
| Priority date | — |
| Expiry date | Jun 16, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99935
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method, apparatus, and article of manufacture for optimizing a query in a computer system, wherein the query is performed by the computer system to retrieve data from a database stored on the computer system. The optimization is performed by identifying a correlated subquery in the query that qualifies for transformation, transitively closing a local filtering predicate within the identified correlated subquery that is on a same column as a correlation join predicate within the identified correlated subquery, and pulling out or bubbling up the transitively closed predicate from the correlated subquery to a parent query block of the query.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.