Database Systems: from File Systems to Modern Database Systems
[ 1 ] Instytut Informatyki (II), Wydział Informatyki i Zarządzania, Politechnika Poznańska | [ P ] employee
2003
chapter in monograph
english
EN Database systems have evolved from simple record-oriented navigational database systems, hierarchical and network systems, into set-oriented systems that gave way to relational database systems. The relational database systems are now evolving into object-relational and multimedia database systems. During the last years, database systems have been used as platforms for managing data for conventional transaction-oriented business applications. As organizations and companies have become more sophisticated, pressure to provide data integration across different, heterogeneous data sources has mounted. The problem how to provide organization-wide uniform access to heterogeneous and autonomous external data sources (file systems, databases, Web pages, etc.) can be addressed, genrally, in three different ways: federated databases, data warehousing systems, and mediated systems. This chapter introduces the reader to basic concepts of database systems and data integration. We start with a presentation of central ideas and foundations of database systems. After tracing the database systems’ evolution, we briefly explore the background, characteristics, advantages and disadvantages of the main database models: hierarchical, network, relational, and object-oriented. Then, the chapter discusses the basic approaches to data integration, and briefly describes each approach in detail.
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