Dynamic partition enhanced inequality joining using a value-count index
US7873629B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 2004 |
| Grant date | Jan 18, 2011 |
| Priority date | — |
| Expiry date | Nov 20, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/2456
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Methods, computer programs, and database systems for performing a database query to join a column A and a column B on an inequality condition are disclosed. A database includes value-count indexes for columns A and B. Minimum and a maximum values for A and B are determined, using the value-count indexes for A and B, respectively. The method includes defining three or more sets of values in A and B, relative to the minimum and maximum values for B and A, respectively. The method includes generating one or more Cartesian products between values in A and B. The database query is performed on a set of values in A and a set of values in B to generate a partial query result. The method includes merging one or more Cartesian products and the partial query result.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.