Synonyms
Definition
Specialization and generalization are main principles of database modeling. Specialization is based on a refinement of types or classes to more specific ones. Generalization maps or groups types or classes to more abstract or combined ones. Typically, generalizations and specializations form a hierarchy of types and classes.
Key Points
Specialization introduces a new entity type by adding specific properties belonging to that type, which are different from the general properties of its more general type. Is-A associations specialize a type to a more specific one. Is-A-Role-Of associations consider a specific behavior of objects. Is-More-Specific-To associations specialize properties of objects of the more general type. The student type and the customer type are specializations of the person type. The rectangle type is specialized to the squaretype by adding restrictions. Different kinds of specialization may be distinguished:...
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Recommended Reading
Ter Bekke J.H. Semantic Data Modeling. Prentice-Hall, London, 1992.
Thalheim B. Entity-Relationship Modeling – Foundations of Database Technology. Springer, Berlin Hiedelberg New York, 2000.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2009 Springer Science+Business Media, LLC
About this entry
Cite this entry
Thalheim, B. (2009). Specialization and Generalization. In: LIU, L., ÖZSU, M.T. (eds) Encyclopedia of Database Systems. Springer, Boston, MA. https://doi.org/10.1007/978-0-387-39940-9_175
Download citation
DOI: https://doi.org/10.1007/978-0-387-39940-9_175
Publisher Name: Springer, Boston, MA
Print ISBN: 978-0-387-35544-3
Online ISBN: 978-0-387-39940-9
eBook Packages: Computer ScienceReference Module Computer Science and Engineering