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Unformatted text preview: ute. Composite and Simple Attributes: Attributes are classified as simple or composite. A composite attribute is an attribute that can be further subdivided to yield additional attributes. For example, the attribute PHONE_NUMBER can be subdivided into area code and exchange number. Single_valued attribute: A single‐valued attribute is an attribute that can have only a single value. For example, a person can have only one SSN. A single valued attribute is not necessarily a simple attribute. For instance, a part’s serial number such as SE‐08‐02‐16745 is single‐valued but is a composite attribute that can be divided into the production region SE, the plant within the region: 08, the shift: 02 and the part number. Multi‐valued Attributes: Multi‐valued attributes are attributes that can have many values. For example, a person may have several college degrees , and a household may have several phone numbers. In the Chen ERM, multivalued attributes are shown by a double line connecting the attribute...
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This document was uploaded on 03/07/2014.
- Spring '09