DBMS Multiple choice Questions and Answers-Data Models

71.	An object can have which of the following multiplicities?
a.	Zero
b.	One
c.	More than one
d.	All of the above.

Answer: (d).All of the above.

72.	Multiplicity is the same as what concept for an ERD?
a.	Relationship
b.	Attribute
c.	Entity
d.	Cardinality

Answer: (d).Cardinality

73.	An abstract class is which of the following?
a.	A class that has direct instances, but whose descendants may have direct instances.
b.	A class that has no direct instances, but whose descendants may have direct instances.
c.	A class that has direct instances, but whose descendants may not have direct instances.
d.	A class that has no direct instances, but whose descendants may not have direct instances

Answer: (b).A class that has no direct instances, but whose descendants may have direct instances.

74.	The term Incomplete for a UML has the same meaning as which of the following for an EER diagram?
a.	Overlapping rule
b.	Disjoint rule
c.	Total specialization rule
d.	Partial specialization rule

Answer: (d).Partial specialization rule

75.	The fact that the same operation may apply to two or more classes is called what?
a.	Inheritance
b.	Polymorphism
c.	Encapsulation
d.	Multiple classification

Answer: (b).Polymorphism

76.	Aggregation is which of the following?
a.	Expresses a part-of relationship and is a stronger form of an association relationship.
b.	Expresses a part-of relationship and is a weaker form of an association relationship.
c.	Expresses an is-a relationship and is a stronger form of an association relationship.
d.	Expresses an is-a relationship and is a weaker form of an association relationship.

Answer: (a).Expresses a part-of relationship and is a stronger form of an association relationship.

77.	Composition is a stronger form of which of the following?
a.	Aggregation
b.	Encapsulation
c.	Inheritance
d.	All of the above.

Answer: (a).Aggregation

78.	Which of the following applies to a class rather than an object?
a.	Query
b.	Update
c.	Scope
d.	Constructor

Answer: (c).Scope

79.	The object-oriented development life cycle is which of the following?
a.	Analysis, design, and implementation steps in the given order and using multiple iterations.
b.	Analysis, design, and implementation steps in the given order and going through the steps no more than one time.
c.	Analysis, design, and implementation steps in any order and using multiple iterations.
d.	Analysis, design, and implementation steps in any order and going through the steps no more than one time.

Answer: (a).Analysis, design, and implementation steps in the given order and using multiple iterations.

80.	The benefits of object-oriented modeling are which of the following?
a.	The ability to tackle more challenging problems
b.	Reusability of analysis, design, and programming results
c.	Improved communication between users, analysts, etc.
d.	All of the above.

Answer: (d).All of the above.