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SER 322 MIDTERM EXAM LATEST VERSION
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SER 322 MIDTEM EXAM LATEST VERSIONEnhanced entity-relationship (EER) model - ANSWER A model that
has resulted from extending the original E-R model with new modeling
constructs.
Subclass - ANSWER A class that extends another class. The subclass
inherits the methods and attributes of the class it extends.
Superclass - ANSWER The parent class from which behavior and
properties are inherited. The super class of all classes in Java is
(eventually) the Object class, and all classes are derived from it.
An entity that is a member of a ... inherits all attributes of the entity as a
member of the ... - ANSWER An entity that is a member of a
SUBCLASS inherits all attributes of the entity as a member of the
SUPERCLASS
Specialization - ANSWER process of defining a set of subclasses of a
superclass
Generalization - ANSWER several classes with common features are
generalized into super classes become its subclasses
Predicated-defined (Condition-defined) - ANSWER when you can
determine exactly those entities will become members of each subclass
by a condition
condition is a constraint that determine subclass member
Ex: Part time vs Full time employee (condition: number of hours worked
> 20)
attribute-defined specialization - ANSWER If all subclasses in a
specialization have a membership condition on same attribute of the
superclass
, Ex: JobType is the defining attribute of specialization {SECRETARY,
TECHNICIAN. ENGINEER} of EMPLOYEE
User-defined - ANSWER if no condition determines membership a user
defined subclass is made
Total Constraint - ANSWER every entity in the superclass must be a
member of some sub class
Partial Constraint - ANSWER its possible that there are some entities
that don't belong to some sub class and that is ok
Disjoint Constraint - ANSWER specifies that the subclasses of the
specialization must be disjointed (an entity can be a member of at most
one of the subclasses of the specialization)
Specified by 'd' in EER diagram
Overlap Constraint - ANSWER the same entity may be a member of
more than one subclass of the specialization
represented by 'o' in EER diagram
Completeness Constraint (Total) - ANSWER specifies that every entity
in the superclass must be a member of some subclass in the
specialization / generalization
shown in EER diagram double line
Completeness Constraint (Partial) - ANSWER allows an entity not to
belong to any of the subclasses
shown in EER diagram single line
Four Types of Specilization/Generalization - ANSWER Disjoin, total
Disjoin, partial
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