WorksheetsChapter 3 - testbank (Database Management Systems)
Total questions: 67
Worksheet time: 34mins
The property by which subtype entities possess the values of all attributes of a supertype is called.
hierarchy reception.
class management.
multiple inheritance.
attribute inheritance.
Which of the following is a generic entity type that has a relationship with one or more subtypes?
Megatype
Supertype
Subgroup
Class
Given the following entities, which of the choices below would be the most complicated? Automobile: VIN, EngineSize, NumberOfDoors, NumberOfPassengers, FuelType, Transmission SUV: VIN, EngineSize, NumberOfPassengers, NoWheelDrive, FuelType, Transmission Truck: VIN, EngineSize, NoWheelDrive, FuelType, Transmission, Payload
Define one vehicle entity type to hold all entities.
Define a separate entity type for each entity.
Define a supertype called vehicle and make each of the entities subtypes.
Keep only the Truck entity type.
Subtypes should be used when:
there are attributes that apply to some but not all instances of an entity type.
supertypes relate to objects outside the business.
the instances of a subtype do not participate in a relationship that is unique to that subtype.
a recursive relationship is needed.
In the figure below, which of the following apply to both OUTPATIENTs and RESIDENT_PATIENTs?
Checkback_Date
Date_Discharged
Patient_Name
XML
In the figure below, which of the following is a subtype of patient?
Outpatient
Physician
Bed
Date_Hired
The process of defining one or more subtypes of a supertype and forming relationships is called:
specialization.
generalization.
creating discord.
selecting classes.
In the figure, to which entity are the entities "CAR" and "TRUCK" generalized?
Make
Vehicle
Model
Price
The process of defining a more general entity type from a set of more specialized entity types is called:
generalization
specialization
normalization
extrapolation
The figure shows ROOM as a supertype with subtypes CLASSROOM, LABORATORY, and OFFICE, each indicated by conditions such as classroom = "Y", lab = "Y", office = "Y". The figure is an example of:
partial specialization
completeness
total specialization
disjointness
The ______ rule specifies that an entity instance of a supertype is allowed not to belong to any subtype.
semi-specialization
total specialization
partial specialization
disjointness
The ______ rule specifies that each entity instance of the supertype must be a member of some subtype in the relationship.
semi-specialization
total specialization
partial specialization
total convergence
Which of the following is a completeness constraint?
Total specialization
Partial generalization
Total recall
Partial hybridization
A(n) ______ constraint is a type of constraint that addresses whether an instance of a supertype must also be an instance of at least one subtype.
disjoint
overlap
completeness
weak
In the figure, a student:
must be a graduate student, an undergraduate, a special student or some other type of student.
must be a graduate student or an undergraduate student.
must be at least a special student.
must be a doctoral student.
The ______ rule specifies that an entity can be a member of only one subtype at a time.
exclusion
disjoint
removal
inclusion
A ______ addresses whether an instance of a supertype may simultaneously be a member of two or more subtypes.
disjointness constraint
disjoint rule
partial specialization
total specialization
In the figure below, the patient must be either an outpatient or a resident patient. This is an example of the ______ rule.
disjoint
specialization
generalization
overlap
An attribute of the supertype that determines the target subtype(s) is called the:
determinant
subtype decision
disjoint indicator
subtype discriminator
The ________ rule states that an entity instance can simultaneously be a member of two (or more) subtypes.
disjoint
overlap
partial specialization
total specialization
The following diagram shows:
total specialization
partial specialization
the overlap rule
subtype discriminator
The subtype discriminator in the figure below is:
Part_Type
Part_No
Manufactured Part
Location
The subtype discriminator is a composite attribute when there is a(n):
overlap rule
disjoint rule
partial specialization
full specialization
The following figure shows an example of:
the disjoint rule.
the completeness rule.
the underdog rule.
the overlap rule.
In a supertype/subtype hierarchy, each subtype has:
only one supertype.
many supertypes.
at most two supertypes.
at least one subtype.
Which of the following statements is true about the figure shown below?
A rental unit must be either an apartment or a house, and cannot be both at the same time.
A rental unit can be an apartment, house or just a rental unit; it may not be more than one at the same time.
A rental unit must be either an apartment or a house, and could be both.
A rental unit can be an apartment, a house or just a rental unit. It could be both an apartment and a house at the same time.
Which of the following statements is true about the figure shown below?
A rental unit must be either an apartment or a house, and cannot be both at the same time.
A rental unit can be an apartment, house or just a rental unit; it may not be more than one at the same time.
A rental unit must be either an apartment or a house, and could be both.
A rental unit can be an apartment, a house or just a rental unit. It could be both an apartment and a house at the same time.
Which of the following statements is true about the figure shown below?
A rental unit must be either an apartment or a house, and cannot be both at the same time.
A rental unit can be an apartment, house or just a rental unit; it may not be more than one at the same time.
A rental unit must be either an apartment or a house, and could be both.
A rental unit can be an apartment, a house or just a rental unit. It could be both an apartment and a house at the same time.
Which of the following statements is true about the figure shown below?
A rental unit must be either an apartment or a house, and cannot be both at the same time.
A rental unit can be an apartment, house or just a rental unit; it may not be more than one at the same time.
A rental unit must be either an apartment or a house, and could be both.
A rental unit can be an apartment, a house or just a rental unit. It could be both an apartment and a house at the same time.
In a supertype/subtype hierarchy, subtypes that are lower in the hierarchy inherit attributes from not only their immediate supertype but from all _______ in the hierarchy.
subtypes
supertypes
constraints
dimensions
The following figure shows a:
disjoint constraint.
completeness constraint.
supertype/subtype hierarchy.
spindle constraint.
Which statement is true about the following diagram?
A person can only be a faculty, student, or staff.
A student can be both an undergraduate and a graduate student at the same time.
All attributes of person and student are inherited by undergraduate.
All attributes of graduate are inherited by person.
An entity cluster is:
a formal method for specifying attributes of related entities.
a set of one or more entity types and associated relationships grouped into a single abstract entity type.
a useful way to present data for a small and fairly simple organization.
a way of developing more granular views of the data model.
The figure below is an example of a(n):
supertype/subtype hierarchy.
hierarchical data model.
entity cluster.
column cluster.
An entity cluster can be formed by:
deleting a supertype and its subtype.
combining metadata.
combining a strong entity and its weak entities.
deleting metadata.
Packaged data models:
are ready to use right out of the box.
require customization.
allow partial specialization.
cannot be used for most applications.
Which of the following is true of packaged data models?
Relationships are connected to the highest-level entity type in an order that makes sense.
All subtype/supertype relationships follow the total specialization and disjoint rules.
No entities on the many sides of a relationship can be weak.
All weak entities are considered strong.
A generic or template data model that can be reused as a starting point for a data modeling project is called a(n):
packaged data model.
universal data model.
enterprise data model.
collection data model.
Using a packaged data model, projects take less time and cost because:
less personnel are required.
essential components and structures are already defined.
there is more time taken to model the enterprise.
packaged data models only run in Oracle.
All of the following are advantages of packaged data models EXCEPT:
packaged data models can be built using proven components evolved from cumulative experiences.
projects take less time and cost less.
the data model is easier to evolve.
more one-to-one relationships give the data model more flexibility.
All of the following are steps to using a packaged data model EXCEPT:
identify the parts of the data model that apply to your data modeling situation.
utilize all business rules that come with the packaged data model.
rename the identified data elements.
map data to be used in packages with existing data in the current databases.
When identifying the parts of the packaged data model that apply to your organization, one should first start with:
entities.
attributes.
primary keys.
relationships.
The third step in the data modeling process with a packaged data model is:
rename identified data elements.
rename relationships.
map data to be used from package to data in current databases.
interview users.
A good method for identifying inconsistencies and finding hidden meaning in the customized purchased data model is:
data analysis.
data volume usage analysis.
user interviews.
data profiling.
The most important challenge of customizing a purchased data model is:
getting user buy-in.
determining the business rules that will be established through the data model.
implementation.
user training.
In packaged data models, strong entities always have ________ between them.
weak entities
1:1 relationships
1:M relationships
M:N relationships
In packaged data models, all subtype/supertype relationships follow the ________ and ________ rules.
partial specialization; disjoint
total specialization; disjoint
total specialization; overlap
partial specialization; overlap
A subtype is a generic entity that has a relationship with one or more entities at a lower level.
True
False
An entity instance of a subtype represents the same entity instance of the supertype.
True
False
A member of a subtype does NOT necessarily have to be a member of the supertype.
True
False
Supertype/subtype relationships should not be used when the instances of a subtype participate in no relationships which are unique to that subtype.
True
False
One of the major challenges in data modeling is to recognize and clearly represent entities that are almost the same.
True
False
The following figure is an example of total specialization.
True
False
Specialization is the reverse of generalization.
True
False
The total specialization rule states that an entity instance of a supertype is allowed not to belong to any subtype.
True
False
Generalization is a top-down process.
True
False
A completeness constraint may specify that each entity of the supertype must be a member of some subtype in the relationship.
True
False
When the total specialization rule is set for a supertype/subtype relationship, one could roughly compare the supertype to an abstract class in object-oriented programming.
True
False
The disjoint rule specifies that if an entity instance of the supertype is a member of one subtype, it MUST simultaneously be a member of another subtype.
True
False
The overlap rule specifies that if an entity instance of the supertype is a member of one subtype, it can simultaneously be a member of two (or more) subtypes.
True
False
The following figure is an example of the overlap rule.
True
False
When subtypes are overlapping, an additional field must be added to the supertype to act as a discriminator.
True
False
There are three separate discriminators in the diagram of ROOM with subtypes CLASSROOM, LABORATORY, and OFFICE because of the overlap rule.
True
False
A subtype can become a supertype if the subtype has other subtypes beneath it.
True
False
The diagram of PERSON with subtypes FACULTY, STUDENT, and STAFF, and STUDENT further specialized into UNDERGRADUATE and GRADUATE, is an example of a supertype/subtype hierarchy.
True
False
In a supertype/subtype hierarchy, attributes are assigned at the highest logical level that is possible in the hierarchy.
True
False
Subtypes at the lowest level of a hierarchy do not inherit attributes from their ancestors.
True
False
