Subtype2-Ch7 - ID# ID# Salary Hourly Salary Rate Stock Plan...

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SUBTYPE/SUPERTYPE Generalization: Creating supertypes Example1: STUDENT Specification: Creating subtypes ISA ISA Relationship between them: ISA Undergrad Stu. Graduate Stu. Example2: ID# -Supertype to subtype relation is a mandatory one going in one direction, and optional ID# one going the other.
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Unformatted text preview: ID# ID# Salary Hourly Salary Rate Stock Plan Why use Subtype/Supertype? 1. Different attributes describe each subtype 2. Each subtype participates in different relationships EMPLOYEE ISA ISA ISA Hourly Employee Manager Employee Salaried Employee...
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This note was uploaded on 11/17/2011 for the course ITM 311 taught by Professor Harrisonmcknight during the Fall '10 term at Michigan State University.

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