In the early 1980s, many Canadian libraries used the GEAC 8000 to convert their manual card catalogues to machine-readable centralized catalogue systems. Example of a centralized database system. With a centralized database system, the DBMS and database are stored at a single site that is used by several other systems too. There are four main distribution systems for database systems and these, in turn, can be used to classify the DBMS. Classification Based on Database Distribution It can be a single-user database system, which supports one user at a time, or a multiuser database system, which supports multiple users concurrently. Classification Based on User NumbersĪ DBMS can be classification based on the number of users it supports. Some examples of object-oriented DBMSs are O2, ObjectStore and Jasmine. The object-oriented models have not caught on as expected so are not in widespread use. Object-oriented database management systems (OODBMS) combine database capabilities with object-oriented programming language capabilities. Object-oriented databases are different from relational databases, which are table-oriented. This model is a database management system in which information is represented in the form of objects as used in object-oriented programming. In recent years, the newer object-oriented data models were introduced. These are all referred to as traditional models because they preceded the relational model. However, they are not commonly used due to their complexity. Other traditional models, such as hierarchical data models and network data models, are still used in industry mainly on mainframe platforms.
Well-known DBMSs like Oracle, MS SQL Server, DB2 and MySQL support this model. The most popular data model in use today is the relational data model. Chapter 6 Classification of Database Management Systemsĭatabase management systems can be classified based on several criteria, such as the data model, user numbers and database distribution, all described below.