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Working paper

Темпоральные расширения в стандарте SQL

Препринты ИСП РАН. Институт системного программирования им. В.П. Иванникова РАН, 2017. № 30.
The paper considers main features, advantages and disadvantages of temporal extensions of the SQL language introduced in the SQL:2011. The basic concepts of the bitemporal model of SQL are introduced: time period, application-time period, system-time period, application-time period table, system-version table. Methods for defining tables with an application-time period, the specifics of executing UPDATE and DELETE operations over such tables, and the specifics of primary and foreign keys in tables with an application time period are discussed. A set of additional predicates for working with tables with a application-time period is described and examples of queries to such tables are given. The rules for determining system-version tables are considered, the features of queries to such tables are discussed. Finally, the possibility of determining the bitemporal tables containing periods of both application and system time is discussed, and examples of queries are given. In the course of the presentation, the advantages and disadvantages of the bitemporal model of SQL are noted.