CS 6400 Exam 3
QUESTIONS AND VERIFIED
CORRECT ANSWERS
GRADED A+ [LATEST] 100%
GUARANTEED PASS
Create a relation ET2 with composite PK, A and B.
A is an FK to ET1 in ET2
How to map super-subtype relationships (mandatory/disjoint)?
ET is supertype
ET1 and ET2 are subtypes - CORRECT ANSWER-Create a relation for ET1 and ET2 with attributes
of ET
How to map super-subtype relationships (mandatory/overlap)?
ET is supertype
ET1 and ET2 are subtypes - CORRECT ANSWER-Create a relation ET
Create a relation ET1 that has ET's PK as its PK and an FK to ET
Create a relation ET2 that has ET's PK as its PK and an FK to ET
,How to map super-subtype relationships (nonmandatory/overlap)?
ET is supertype
ET1 and ET2 are subtypes - CORRECT ANSWER-Create a relation ET
Create a relation ET1 that has ET's PK as its PK and an FK to ET
Create a relation ET2 that has ET's PK as its PK and an FK to ET
Difference between mapping nonmandatory/overlap and mandatory/overlap super-subtype
relationships? - CORRECT ANSWER-None
How to map super-subtype relationships (nonmandatory/disjoint)? - CORRECT ANSWER-Create
a relation ET
Create a relation ET1 that inherits PK of ET as its PK
Create a relation ET2 that inherits PK of ET as its PK
No foreign keys
How to map union types? - CORRECT ANSWER-Create a relation ET that has an artificial
identifier
Create a relation ET1 with its identifying property C and FK to ET
Create a relation ET2 with its identifying property D and FK to ET
, How does the relational model represent the database? - CORRECT ANSWER-As a collection of
relations where each relation resembles a table of values or a flat file of records
Each row in the table represents a collection of related data values
Domain D is a... - CORRECT ANSWER-set of atomic (indivisible) values
What is a common method of specifying a domain? - CORRECT ANSWER-To specify a data type
from which the data values forming the domain are drawn. It is also useful to specify a name for
the domain and data type or format
Example of a domain - CORRECT ANSWER-usa_phone_numbers (string in the form of ddd-ddd-
dddd) is the set of 10 digit phone numbers valid in the US
Cartesian product specifies what? - CORRECT ANSWER-all possible combinations of values from
the underlying domains
Current relation state - CORRECT ANSWER-a relation state at a given time - reflects only the
valid tuples that represent a particular state of the real world
Characteristics of relations - CORRECT ANSWER-- ordering of tuples
- ordering of values within a tuple and an alternative definition of a relation
- values and NULLs in the tuples
- interpretation (meaning) of a relation
Ordering of tuples - CORRECT ANSWER-tuples in a relation do not have any particular order
QUESTIONS AND VERIFIED
CORRECT ANSWERS
GRADED A+ [LATEST] 100%
GUARANTEED PASS
Create a relation ET2 with composite PK, A and B.
A is an FK to ET1 in ET2
How to map super-subtype relationships (mandatory/disjoint)?
ET is supertype
ET1 and ET2 are subtypes - CORRECT ANSWER-Create a relation for ET1 and ET2 with attributes
of ET
How to map super-subtype relationships (mandatory/overlap)?
ET is supertype
ET1 and ET2 are subtypes - CORRECT ANSWER-Create a relation ET
Create a relation ET1 that has ET's PK as its PK and an FK to ET
Create a relation ET2 that has ET's PK as its PK and an FK to ET
,How to map super-subtype relationships (nonmandatory/overlap)?
ET is supertype
ET1 and ET2 are subtypes - CORRECT ANSWER-Create a relation ET
Create a relation ET1 that has ET's PK as its PK and an FK to ET
Create a relation ET2 that has ET's PK as its PK and an FK to ET
Difference between mapping nonmandatory/overlap and mandatory/overlap super-subtype
relationships? - CORRECT ANSWER-None
How to map super-subtype relationships (nonmandatory/disjoint)? - CORRECT ANSWER-Create
a relation ET
Create a relation ET1 that inherits PK of ET as its PK
Create a relation ET2 that inherits PK of ET as its PK
No foreign keys
How to map union types? - CORRECT ANSWER-Create a relation ET that has an artificial
identifier
Create a relation ET1 with its identifying property C and FK to ET
Create a relation ET2 with its identifying property D and FK to ET
, How does the relational model represent the database? - CORRECT ANSWER-As a collection of
relations where each relation resembles a table of values or a flat file of records
Each row in the table represents a collection of related data values
Domain D is a... - CORRECT ANSWER-set of atomic (indivisible) values
What is a common method of specifying a domain? - CORRECT ANSWER-To specify a data type
from which the data values forming the domain are drawn. It is also useful to specify a name for
the domain and data type or format
Example of a domain - CORRECT ANSWER-usa_phone_numbers (string in the form of ddd-ddd-
dddd) is the set of 10 digit phone numbers valid in the US
Cartesian product specifies what? - CORRECT ANSWER-all possible combinations of values from
the underlying domains
Current relation state - CORRECT ANSWER-a relation state at a given time - reflects only the
valid tuples that represent a particular state of the real world
Characteristics of relations - CORRECT ANSWER-- ordering of tuples
- ordering of values within a tuple and an alternative definition of a relation
- values and NULLs in the tuples
- interpretation (meaning) of a relation
Ordering of tuples - CORRECT ANSWER-tuples in a relation do not have any particular order
