Database Models

Abstract A database model is a tool for describing the data that are to be stored in a database, providing an abstract, conceptual layer that protects the users and developers of database applications from the need to be concerned with low‐level implementation details. Many different database models have been developed over the years, ranging from database‐dependent models that are associated with specific types of database management systems to database‐independent models that provide conceptual modeling front‐ends for database application development. This article provides an overview of the basic concepts associated with conceptual, relational, and object‐based database models. Conceptual modeling techniques are presented using the entity‐relationship model and the semantic extensions of the enhanced entity‐relationship model. The relational data model is presented as one of the most widely used models associated with a specific type of database management system. Techniques for mapping from conceptual models to the relational model are also presented. Throughout the article, the role of database semantics and semantic integrity constraints is emphasized. The article ends with an overview of the object‐oriented data model and the object‐relational data model, with a discussion of new directions for data modeling in advanced applications. Fundamental Data Modeling Concepts Development of Database Models Conceptual Data Modeling The Relational Data Model Object‐Based Models Summary