Jump to content

Object–relational database

From Wikipedia, the free encyclopedia
This is an old revision of this page, as edited by 203.200.183.10 (talk) at 06:46, 30 June 2009 (→Comparison to RDBMS). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

An object-relational database (ORD), or object-relational database management system (ORDBMS), is a database management system (DBMS) similar to a relational database, but with an object-oriented database model: objects, classes and inheritance are directly supported in database schemas and in the query language. In addition, it supports extension of the data model with custom data-types and methods.

Example of a Object-Oriented Database Model.[1]

An object-relational database can be said to provide a middle ground between relational databases and object-oriented databases (OODBMS). In object-relational databases, the approach is essentially that of relational databases: the data resides in the database and is manipulated collectively with queries in a query language; at the other extreme are OODBMSes in which the database is essentially a persistent object store for software written in an object-oriented programming language, with a programming API for storing and retrieving objects, and little or no specific support for querying.

History

Object-relational database management systems grew out of research that occurred in the early 1990s. That research extended existing relational database concepts by adding object concepts. The researchers aimed to retain a declarative query-language based on predicate calculus as a central component of the architecture. Probably the most notable research project, Postgres (UC Berkeley), spawned two products tracing their lineage to that research: Illustra and PostgreSQL.

In the mid-1990s, early commercial products appeared. These included Illustra[2] (Illustra Information Systems, acquired by Informix Software which was in turn acquired by IBM), Omniscience (Omniscience Corporation, acquired by Oracle Corporation and became the original Oracle Lite), and UniSQL (UniSQL, Inc., acquired by KCOMS). Ukrainian developer Ruslan Zasukhin, founder of Paradigma Software, Inc., developed and shipped the first version of Valentina database in the mid-1990s as a C++ SDK. By the next decade, PostgreSQL had become a commercially viable database and is the basis for several products today which maintain its ORDBMS features.

Computer scientists came to refer to these products as "object-relational database management systems" or ORDBMSs.[3]

Many of the ideas of early object-relational database efforts have largely become incorporated into SQL:1999. In fact, any product that adheres to the object-oriented aspects of SQL:1999 could be described as an object-relational database management product. For example, IBM's DB2, Oracle database, and Microsoft SQL Server, make claims to support this technology and do so with varying degrees of success.

References

  1. ^ Data Integration Glossary, U.S. Department of Transportation, August 2001.
  2. ^ Stonebraker, Michael with Moore, Dorothy. Object-Relational DBMSs: The Next Great Wave. Morgan Kaufmann Publishers, 1996. ISBN 1-55860-397-2.
  3. ^ There was, at the time, some dispute whether the term was coined by Michael Stonebraker of Illustra or Won Kim of UniSQL.
Wikimedia Commons has media related to Object-Oriented models.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Object–relational_database&oldid=299462340"