Cost-based maintenance of materialized views
US6026390A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 9, 1997 |
| Grant date | Feb 15, 2000 |
| Priority date | — |
| Expiry date | Jul 9, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99937
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of incrementally maintaining a first materialized view of data in a database, by means of an additional materialized view, first determines whether a cost in time of incrementally maintaining the first materialized view with the additional materialized view is less than the cost of incrementally maintaining the first materialized view without the additional materialized view. The method creates the additional materialized view only if the cost in time is less therewith. Determining whether the cost of employing an additional materialized view is less includes using an expression directed acyclic graph that corresponds to the first materialized view. Another method of determining whether the cost is less includes pruning an expression directed acyclic graph to produce a single expression tree, and using the single expression tree to determine whether the cost is less. Both the expression directed acyclic graph and the single expression tree contain equivalence nodes. One or more possible materialized views are selected by marking the equivalence nodes, and materializing one or more views corresponding to the marked equivalence nodes. One or more possible materialized views …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.