Attribute domain
title: "Attribute domain" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["type-theory", "database-theory"] topic_path: "technology/computing" source: "https://en.wikipedia.org/wiki/Attribute_domain" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
In computing, the attribute domain is the set of values allowed in an attribute.
For example: Rooms in hotel (1–300) Age (1–99) Married (yes or no) Nationality (Nepalese, Indian, American, or British) Colors (Red, Yellow, Green)
For the relational model it is a requirement that each part of a tuple be atomic. The consequence is that each value in the tuple must be of some basic type, like a string or an integer. For the elementary type to be atomic it cannot be broken into more pieces. Alas, the domain is an elementary type, and attribute domain the domain a given attribute belongs to an abstraction belonging to or characteristic of an entity.
For example, in SQL, one can create their own domain for an attribute with the command
::code[lang=sql] CREATE DOMAIN SSN_TYPE AS CHAR(9); ::
The above command says: "Create a datatype SSN_TYPE that is of character type with size 9".
References
References
- (1999). "A Guided Tour of Relational Databases and Beyond". Springer.
- Narang, Rajesh. (2011). "Database Management Systems". PHI Learning Pvt. Ltd..
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