Generalization bottom up design process combines number of entity sets - Database

Q.  Generalization is a bottom up design process that combines a number of entity sets, which share the same features into a higher level entity set.
- Published on 28 Aug 15

a. True
b. False

ANSWER: True
 

    Discussion

  • Nirja Shah   -Posted on 30 Oct 15
    Generalization
    - A bottom-up design process – combine a number of entity sets that share the same features into a higher-level entity set.

    - Specialization and generalization are simple inversions of each other; they are represented in an E-R diagram in the same way.

    - The terms specialization and generalization are used interchangeably.

    - Can have multiple specializations of an entity set based on different features.

    - E.g. permanent-employee vs. temporary-employee, in addition to officer vs. secretary vs. teller

    - Each particular employee would be
    1. a member of one of permanent-employee or temporary-employee,
    2. and also a member of one of officer, secretary, or teller

    - The ISA relationship also referred to as superclass - subclass relationship

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