6305851
Descrição
Quiz por Angel Perez, atualizado more than 1 year ago
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Criado por Angel Perez
mais de 7 anos atrás
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Questão 1
Questão
E-R models are expressed using a single standardized set of universally accepted symbols.
Responda
- True
- False
Questão 2
Questão
An entity is something in the users’ work environment that the users want to track.
Responda
- True
- False
Questão 3
Questão
Entities of a given type are grouped into entity classes.
Responda
- True
- False
Questão 4
Questão
An entity class is described by the structure of the entities in that class.
Responda
- True
- False
Questão 5
Questão
An entity instance of an entity class is the representation of a particular entity and is described by the values of the attributes of the entity.
Responda
- True
- False
Questão 6
Questão
In E-R modeling, entities within an entity class may have different attributes.
Responda
- True
- False
Questão 7
Questão
In E-R modeling, an attribute may be either composite or multi-valued, but it cannot be both.
Responda
- True
- False
Questão 8
Questão
An identifier of an entity instance must consist of one and only one attribute.
Responda
- True
- False
Questão 9
Questão
A “composite identifier” is defined as a composite attribute that is an identifier.
Responda
- True
- False
Questão 10
Questão
An identifier may be either unique or nonunique.
Responda
- True
- False
Questão 11
Questão
E-R modeling recognizes both relationship classes and relationship instances.
Responda
- True
- False
Questão 12
Questão
Relationships do not have attributes.
Responda
- True
- False
Questão 13
Questão
A single relationship class involves only one entity class.
Responda
- True
- False
Questão 14
Questão
A binary relationship is a relationship based on numerical entity instance identifiers.
Responda
- True
- False
Questão 15
Questão
The degree of a relationship is expressed as the relationship’s maximum cardinality.
Responda
- True
- False
Questão 16
Questão
A relationship’s minimum cardinality indicates whether or not an entity must be involved in the relationship.
Responda
- True
- False
Questão 17
Questão
Relationships among instances of a single entity class are called redundant relationships.
Responda
- True
- False
Questão 18
Questão
A weak entity is an entity that cannot exist in the database without (and is logically dependent upon) another type of entity also existing in the database.
Responda
- True
- False
Questão 19
Questão
ID-dependent entities are a common type of weak entity.
Responda
- True
- False
Questão 20
Questão
All weak entities must have a minimum cardinality of 1 on the entity on which it depends.
Responda
- True
- False
Questão 21
Questão
Multi-valued attributes are represented in E-R diagrams by creating a new weak entity to represent the multi-valued attribute and creating a 1:N relationship.
Responda
- True
- False
Questão 22
Questão
Subtype entities are used to produce a closer-fitting model when an entity has sets of optional attributes.
Responda
- True
- False
Questão 23
Questão
Entities with an IS-A relationship should have the same identifier.
Responda
- True
- False
Questão 24
Questão
Inheritance in a generalization hierarchy means that the supertype entity inherits all the attributes of the subtype entity.
Responda
- True
- False
Questão 25
Questão
It is not important to document business rules during data modeling since they will be enforced by the application programs.
Responda
- True
- False
Questão 26
Questão
UML is intended for modeling and designing object-oriented programs and applications.
Responda
- True
- False
Questão 27
Questão
For database design, UML-style E-R diagrams must be treated very differently from traditional E-R diagrams because of their object-oriented background.
Responda
- True
- False
Questão 28
Questão
Maximum cardinalities are represented in UML-style E-R diagrams with the same notation (1:1, 1:N, N:M) as in traditional E-R diagrams.
Responda
- True
- False
Questão 29
Questão
In UML-style E-R diagrams, a weak entity is shown by placing a filled-in diamond on the parent of the weak entity.
Responda
- True
- False
Questão 30
Questão
One weakness of UML-style E-R diagrams is that there is no means of distinguishing between a weak entity that is ID-dependent and a weak entity that is not ID-dependent.
Responda
- True
- False
Questão 31
Questão
UML-style E-R diagrams allow for the existence of class attributes, which are attributes that pertain to the collection of all entities within that class not to the individual entity instances
Responda
- True
- False
Questão 32
Questão
UML-style E-R diagrams allow for three different levels of visibility of attributes.
Responda
- True
- False
Questão 33
Questão
UML-style E-R diagrams introduce object-oriented notation that is of limited practical value in traditional, relational database design.
Responda
- True
- False
Questão 34
Questão
The goal of data models is to strive to produce the most accurate model of the real world as possible.
Responda
- True
- False
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