Basic Concepts(Cont) Attributes An entity is represented by a set of attributes, that is descriptive properties possessed by all members of an entity set Domain- the set of permitted values for each attribute Attribute types Simple and composite attributes Single-valued and multi-valued attributes E.g. multivalued attribute: phone-numbers Derived attributes Can be computed from other attributes E.g. age, given date of birth Database System Concepts 2 @Silberschatz, Korth and SudarshanDatabase System Concepts 2.4 ©Silberschatz, Korth and Sudarshan Basic Concepts (Cont.) Attributes An entity is represented by a set of attributes, that is descriptive properties possessed by all members of an entity set. Domain – the set of permitted values for each attribute Attribute types: Simple and composite attributes. Single-valued and multi-valued attributes – E.g. multivalued attribute: phone-numbers Derived attributes – Can be computed from other attributes – E.g. age, given date of birth