Method, computer program product, and system for rewriting database queries in a heterogenous environment
US6526403B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 1999 |
| Grant date | Feb 25, 2003 |
| Priority date | — |
| Expiry date | Dec 17, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99934
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method, computer product, and system for rewriting database without decreasing pushdownability is provided. First, a pushdown analysis of the query in its entirety is performed prior to the application of any query rewrite rules in order to establish a baseline on pushdownability for the query. The results of this analysis is stored with the internal query representation. After each rule is applied to rewrite a portion of a query, that rewritten portion is analyzed again for pushdownability. If pushdownability is not decreased, then the rewritten query remains and the internal representation of the query is updated to reflect the pushdownability of that portion. If pushdownability is decreased, then an undo operation is applied to the rewritten portion of the query to back out the effects of the rule and leave the query in the same state as before the rewrite. Finally, additional rewrite rules that are directed to the heterogeneous database environment are also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.