Database management system for controlling concurrent access to a database
US4627019A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 8, 1982 |
| Grant date | Dec 2, 1986 |
| Priority date | — |
| Expiry date | Jul 8, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99938
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of assuring that each of a plurality of contemporaneously active database transactions comprising at least one read transaction and at most one update transaction has a consistent view of a database storing a plurality of versions of a relation. A transaction has a consistent view of a database if the data available to a transaction are not changed during its execution. An access dictionary is stored comprising an array of access blocks each defining the database location of one of the relation versions. At any given time, only one of the relation versions is defined as current. A relation dictionary comprising an array of relation blocks is stored such that as each database transaction is begun, a relation block associated with that database transaction is stored defining the access block defining the database location of the relation version then defined as current. For the update transaction, a new access block in the access dictionary is stored defining a new database location to be used for storing a new relation version. The relation block associated with the update transaction is modified to define the new access block and the new relation version is stored in the n…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.