Processing a sequence of outer joins
US8688722B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 2009 |
| Grant date | Apr 1, 2014 |
| Priority date | — |
| Expiry date | Sep 5, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/2456
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
To process a sequence of outer joins in a database system, the database system performs a first outer join of the sequence of outer joins. A result of the first outer join is stored in a result table stored across plural storage modules of the database system. At least a subset of records of the result table is redistributed across the storage modules according to a first join attribute of the result table, where any record of the result table that has a null value for the first join attribute is not redistributed. A second outer join of the sequence is performed using the redistributed result table and another table, where the second outer join is based on the first join attribute of the result table.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.