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Wpływ przyjętego modelu wersjonowania danych na efektywność relacyjnej bazy danych

Bach M., Stańczak M., Werner A.

Studia Informatica

2009

Vol. 30, nr 2B

253-263

W pracy skoncentrowano się na zagadnieniach związanych z wersjonowaniem relacyjnej bazy danych oraz przedstawiono propozycje dwóch rozwiązań, pozwalających na zapamiętanie i odtwarzanie stanu bazy z dowolnego momentu czasu. Dodatkowo przeprowadzono testy, które wskazały potencjalne obszary zastosowań zaproponowanych mechanizmów wersjonowania.

The fundamental concepts of relational data versioning possibilities and the proposals of full and incremental versioning methods are contained in this paper. Additionally, applied method influence to the database size and the time of database state restoring are presented in this article.

Formal approach to modelling a multiversion data warehouse

Bębel B., Królikowski Z., Wrembel R.

Bulletin of the Polish Academy of Sciences. Technical Sciences

2006

Vol. 54, nr 1

51-62

A data warehouse (DW) is a large centralized database that stores data integrated from multiple, usually heterogeneous external data sources (EDSs). DW content is processed by so called On-Line Analytical Processing applications, that analyze business trends, discover anomalies and hidden dependencies between data. These applications are part of decision support systems. EDSs constant1y change their content and often change their structures. These changes have to be propagated into a DW, causing its evolution. The propagation of content changes is implemented by means of materialized views. Whereas the propagation of structural changes is mainly based on temporal extensions and schema evolution, that limits the application of these techniques. our approach to handling the evolution of a DW is based on schema and data versioning. This mechanism is the core of, so called, a multiversion data warehouse. A multiversion DW is composed of the set of its versions. A single DW version is in turn composed of a schema version and the set of data described by Ibis schema version. Every DW version stores a DW stale which is valid within a certain time period. In Ibis paper we present: (1) a formal model of a multiversion data warehouse, (2) the set of operators with their formal semantics that support a DW evolution, (3) the impact analysis of the operators on DW data and user analytical queries. The presented formal model was a basis for implementing a multiversion DW prototype system.