Multiplicity is the same as what concept for an ERD?
Answer: D
Correct answer: Cardinality
Multiplicity in UML states how many instances of one class may be associated with an instance of another, which is exactly what cardinality expresses on an entity-relationship diagram. The notation differs - 0..1, 1..*, 3..5 against the crow’s foot - but the concept is the same.
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The fact that the same operation may apply to two or more classes is called what?
Answer: B
Correct answer: Polymorphism
Polymorphism means many forms: the same operation name applies across several classes, each supplying its own implementation. A caller invokes print or area without knowing which class it is dealing with, and the right code runs. Inheritance is the mechanism that most often makes it possible, but the two are not the same thing.
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Which of the following statement is true concerning objects and/or classes?
Answer: A
Correct answer: An object is an instance of a class.
The class is the definition and the object is a particular thing built to it - the class Customer against the object representing one named customer. Both encapsulate operations as well as data, which is the point of the object-oriented approach and what distinguishes an object from a record.
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An operation that alters the state of an object is known as a constructor operation.
Answer: B
Correct answer: False
An operation that alters the state of an object is an update or modifier operation. A constructor creates a new instance; it does not alter an existing one. The third kind, a query, reports on the state without changing it.
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A UML diagram includes which of the following?
Answer: D
Correct answer: All of the above.
The standard UML class symbol is a rectangle divided into three compartments by horizontal lines: the class name at the top, the attributes in the middle and the operations at the bottom. The lower compartments may be suppressed in a diagram where only the relationships matter, but all three belong to the notation.
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An object can have which of the following multiplicities?
Answer: D
Correct answer: All of the above.
Multiplicity states how many objects may participate, and the permitted values include zero, exactly one, and many. An optional association is written 0..1, a mandatory one 1, and an unbounded one 1..* or *. It is the zero case that distinguishes an optional participation from a required one.
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An aggregation is a stronger form of association relationship and is represented with a solid diamond at the aggregate end.
Answer: B
Correct answer: False
The first half is right and the second is not. Aggregation is drawn with a hollow diamond at the aggregate end; the solid diamond is reserved for composition, the stronger form in which the part is unshared and shares the whole’s lifetime.
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The benefits of object-oriented modeling are which of the following?
Answer: D
Correct answer: All of the above.
All three are claimed for the approach and are related. A single set of concepts runs from analysis through design to code, so results are reusable and the model is comprehensible to users and analysts alike; and because the model matches the problem domain rather than the implementation, larger problems become tractable.
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A method defines the form or protocol of the operation, but not its implementation.
Answer: B
Correct answer: False
The terms are the other way round. An operation specifies the form or protocol - the name, the parameters and the result - while a method is the body that implements it. The distinction is what makes polymorphism expressible: one operation may have several methods, one in each class.
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A class is a concept, abstraction, or thing that makes sense in an application context.
Answer: A
Correct answer: True
This is the definition a class carries in analysis: something meaningful in the problem domain, whether a tangible thing, a role, an event or an abstraction. Identifying classes is therefore a modelling judgement about the application rather than a programming decision, which is why the same classes survive into design.
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