Chapter 4 Fundamentals of DB Systems Midterm Exam And 100% Accurate Answers.
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Course
Fundamentals of Database Systems
Institution
Fundamentals Of Database Systems
Subclass or Subtype of an entity type - Answer The numerous subgroupings of an entity that are meaningful and need to be represented explicitly because of their significance to the database application
Super class or supertype - Answer The entity for which a subtype belongs
Class/subcla...
Chapter 4 Fundamentals of DB Systems
Midterm Exam And 100% Accurate
Answers.
Subclass or Subtype of an entity type - Answer The numerous subgroupings of an entity that are
meaningful and need to be represented explicitly because of their significance to the database
application
Super class or supertype - Answer The entity for which a subtype belongs
Class/subclass relationship - Answer The relationship between a super class in any of it subclasses
Type inheritance - Answer When an entity that is a member of a subclass in here it's all the attributes
of the entity as a member of the superclass
Specialization - Answer The process of defining a set of subclasses of an entity type
Specific or local attributes - Answer Attributes that apply only to entities of a particular subclass
Generalization - Answer Suppressing the differences among several entity types, identifying their
common features, and then generalizing them into a single superclass of which the original entity types
are special subclasses. In other words the process of defining a generalized entity type from the given
entity types
Predicate - defined/condition - defined subclasses - Answer A condition placed on The value of an
attribute in the super class, which will determine exactly the entities that will become members of each
subclass.
Attribute - defined specialization - Answer When all subclasses in the specialization have their
membership condition on the same attributes of the superclass
, User - defined subclass - Answer When we do not have a condition for determining membership in a
subclass
Disjointness constraint - Answer A constraint that specifies that the subclasses of the specialization
must be disjoint sets. This means that an entity can be a member of at most one of the subclasses of the
specialization.
Overlapping constraint - Answer And entity may be a member of more than one subclassed of the
specialization this case, which is the default, is displayed by placing in O in the circle
Completeness or totalness constraint - Answer Specifies that every entity in the superclass must be a
member of at least one subclass in the specialization
Disjointness, completeness - Answer Two constraints that applied to a specialization
Partial specialization - Answer Allows an entity NOT to belong to any of the subclasses
True - Answer In general a super class that was addenda fied through the generalize Asian process
usually is total, because the superclass is derived from the subclasses and hence contains only the
entities that are in the subclasses
Total generalization - Answer When a superclass contains only the entities that are in the subclasses
True - Answer Disjointness constraints are independent. The four possible constraints on a
specialization are disjoint, total
Disjoint, partial
Overlapping, total
Overlapping, partial
True - Answer Deleting an entity for my superclass implies that it is automatically deleted from all the
subclasses to which it belongs
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