Attributes and Domain

  • An attribute is a property used to describe the specific feature of the entity.
  • So to describe an entity entirely, a set of attributes is used.
    eg:- A Student entity may be described by the Studentís name, age, address, course, etc.

  • The set of possible values that can be attached to the attribute of an entity type is called the domain of the attribute.
  • An attribute cannot contain a value outside this domain.
    eg:- for PERSON entity PERSON_ID has a specific domain, integer values say from 1 to 100.