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ISA 245 Exam 2 With 100% Correct And Verified Answers
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ISA 245 Exam 2 With 100% Correct And Verified Answers
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ISA 245 Exam 2 With 100% Correct AndVerified Answers
Entity supertype - Correct Answer-: Generic entity type
related to one or more entity subtypes
Contains common characteristics
Entity subtype - Correct Answer-Contains unique
characteristics of each entity subtype
Criteria to determine the usage
There must be different, identifiable kinds of the entity in
the user's environment
The different kinds of instances should each have one or
more attributes that are unique to that kind of instance
What is the specialization hierarchy? - Correct Answer-
Depicts arrangement of higher-level entity Supertypes and
lower-level entity subtypes
Relationships are described in terms of "is-a" relationships
Subtype exists within the context of a supertype
Every subtype has one supertype to which it is directly
related
Supertype can have many subtypes
Provides the means to:
Support attribute inheritance
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, Define a special supertype attribute known as the subtype
discriminator
Define disjoint/overlapping constraints and complete/partial
constraints
Use your own examples to explain the concepts of
inheritance, category subtype discriminator, disjoin and
overlapping constraints, and completeness constraint. -
Correct Answer-Inheritance Enables an entity subtype to
inherit attributes and relationships of the supertype, All
entity subtypes inherit their primary key attribute from
their supertype, Entity subtypes inherit all relationships in
which supertype entity participates
A subtype discriminator is the attribute in the supertype
entity that determines to which subtype the supertype
occurrence is related.
Disjoint subtypes: Contain a unique subset of the supertype
entity set
Known as nonoverlapping subtypes
Implementation is based on the value of the subtype
discriminator attribute in the supertype
Overlapping subtypes: Contain nonunique subsets of the
supertype entity set
Implementation requires the use of one discriminator
attribute for each subtype
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