Cs430 Exam || 100% Certified Answers.
A relationship in a database is which of the following? correct answers An association between
entities
T/F: Atomicity refers to the requirements that either all of a transaction must occur or none of it.
correct answers True
T/F: The person that has central control over a DBMS is called a DataBase Administrator (DBA)
correct answers True
T/F: An attribute takes a null value when the value of the attribute is computed to be zero.
correct answers False
T/F: The schema developed at the conceptual design phase provides a detailed overview of the
enterprise. correct answers True
One very important advantage of using a DBMS is that it offers data independence. This is
defined as what? correct answers Application programs are insulated from changes in the way
data is structured and stored.
A language that is used to express database queries and updates is called: correct answers A data
manipulation language
A language in which a user specifies a database schema is called: correct answers A data
definition language
Typical functions of a database administrator would include which of the following? correct
answers Storage structure and access-method definition
Schema definition.
Security and access rights definitions.
T/F: The DDL interpreter of the query processor is responsible for query optimization. correct
answers False
T/F: It is desirable for all users to see the entire logical model. correct answers False
Which of the following are components of the storage manager? correct answers Buffer Manager
Authorization and integrity manager
Transaction manager
File Manager
Which of the following are the data structures the storage manager implements as part of the
physical system? correct answers Indices
Data files
Data dictionary
,A data dictionary contains ____________________, data about data. correct answers metadata
Table: correct answers collection of relations / entity set
Row: correct answers represents a relationship among a set of values/entity
Column headers are: correct answers attributes
Domain: correct answers set of permitted values
Which of the following are disadvantages to file processing systems? correct answers Operating
systems provide only a password mechanism for access control.
We must protect the data from inconsistent changes made by different users accessing the data
concurrently.
We need special programs to answer each question a user may want to ask about the data.
We must ensure the data is restored to a consistent state if the system cashes while changes are
being made.
T/F: It is not possible for several attributes to have the same domain, we require they be unique.
correct answers False
A ___________________ is a minimal superkey. correct answers Candidate key
T/F: Relational Algebra is a non-procedural query language. correct answers False
T/F: For each attribute, there is a set of permitted values called the domain or the value set.
correct answers True
The logical design of the database is called which of the following? correct answers Database
schema
T/F: The schema of a relation changes when tuples are added to the database. correct answers
False
T/F: The order of how a tuple appears in a relations is extremely important as that is what
determines the primary key. correct answers False
An instance of a relation is which of the following: correct answers A set of tuples, also called
records, in which each tuple has the same number of fields as the relation schema.
A domain is _____________________ if the elements of the domain are considered to be
indivisible units. correct answers Atomic
, How many tuples are there in a row of a table with a column header with 3 attributes? correct
answers a 3-tuple
Superkey: correct answers a set of one or more attributes that allow us to identify an entity in the
entity set
Candidate key: correct answers a superkey that contains no extraneous attributes
Primary key: correct answers A candidate key that is chosen by the database designer as the
principal means of identifying entities within an entity set
Foreign key: correct answers an attribute in one relation that references the primary key of
another relation
A ___________________ is a candidate key. correct answers Primary key
Procedural query language: correct answers The user instructs the system to perform a sequence
of operations
Non-procedural query language: correct answers The user describes the desired information
Which statements about keys are true? correct answers A primary key is a candidate key and a
superkey.
A snapshot of the data in a database at a given time is called which of the following? correct
answers Database instance
T/F: A relation schema consists of a list of attributes and their corresponding domains. correct
answers True
One domain value that is a member of any possible domain is what? correct answers Null
Selection: correct answers Return rows of the input relation that satisfy the predicate
Projection: correct answers Output specified attributes from all rows of the input relation.
Remove duplicate tuples from the output.
Natural join: correct answers Output pairs of rows from the two input relations that have the
same value on all attributes that have the same name.
Cartesian product: correct answers Output all pairs of rows from the two input relations
(regardless of whether or not they have the same values on common attributes)
Union: correct answers Output the union of tuples from the two input relations.
A relationship in a database is which of the following? correct answers An association between
entities
T/F: Atomicity refers to the requirements that either all of a transaction must occur or none of it.
correct answers True
T/F: The person that has central control over a DBMS is called a DataBase Administrator (DBA)
correct answers True
T/F: An attribute takes a null value when the value of the attribute is computed to be zero.
correct answers False
T/F: The schema developed at the conceptual design phase provides a detailed overview of the
enterprise. correct answers True
One very important advantage of using a DBMS is that it offers data independence. This is
defined as what? correct answers Application programs are insulated from changes in the way
data is structured and stored.
A language that is used to express database queries and updates is called: correct answers A data
manipulation language
A language in which a user specifies a database schema is called: correct answers A data
definition language
Typical functions of a database administrator would include which of the following? correct
answers Storage structure and access-method definition
Schema definition.
Security and access rights definitions.
T/F: The DDL interpreter of the query processor is responsible for query optimization. correct
answers False
T/F: It is desirable for all users to see the entire logical model. correct answers False
Which of the following are components of the storage manager? correct answers Buffer Manager
Authorization and integrity manager
Transaction manager
File Manager
Which of the following are the data structures the storage manager implements as part of the
physical system? correct answers Indices
Data files
Data dictionary
,A data dictionary contains ____________________, data about data. correct answers metadata
Table: correct answers collection of relations / entity set
Row: correct answers represents a relationship among a set of values/entity
Column headers are: correct answers attributes
Domain: correct answers set of permitted values
Which of the following are disadvantages to file processing systems? correct answers Operating
systems provide only a password mechanism for access control.
We must protect the data from inconsistent changes made by different users accessing the data
concurrently.
We need special programs to answer each question a user may want to ask about the data.
We must ensure the data is restored to a consistent state if the system cashes while changes are
being made.
T/F: It is not possible for several attributes to have the same domain, we require they be unique.
correct answers False
A ___________________ is a minimal superkey. correct answers Candidate key
T/F: Relational Algebra is a non-procedural query language. correct answers False
T/F: For each attribute, there is a set of permitted values called the domain or the value set.
correct answers True
The logical design of the database is called which of the following? correct answers Database
schema
T/F: The schema of a relation changes when tuples are added to the database. correct answers
False
T/F: The order of how a tuple appears in a relations is extremely important as that is what
determines the primary key. correct answers False
An instance of a relation is which of the following: correct answers A set of tuples, also called
records, in which each tuple has the same number of fields as the relation schema.
A domain is _____________________ if the elements of the domain are considered to be
indivisible units. correct answers Atomic
, How many tuples are there in a row of a table with a column header with 3 attributes? correct
answers a 3-tuple
Superkey: correct answers a set of one or more attributes that allow us to identify an entity in the
entity set
Candidate key: correct answers a superkey that contains no extraneous attributes
Primary key: correct answers A candidate key that is chosen by the database designer as the
principal means of identifying entities within an entity set
Foreign key: correct answers an attribute in one relation that references the primary key of
another relation
A ___________________ is a candidate key. correct answers Primary key
Procedural query language: correct answers The user instructs the system to perform a sequence
of operations
Non-procedural query language: correct answers The user describes the desired information
Which statements about keys are true? correct answers A primary key is a candidate key and a
superkey.
A snapshot of the data in a database at a given time is called which of the following? correct
answers Database instance
T/F: A relation schema consists of a list of attributes and their corresponding domains. correct
answers True
One domain value that is a member of any possible domain is what? correct answers Null
Selection: correct answers Return rows of the input relation that satisfy the predicate
Projection: correct answers Output specified attributes from all rows of the input relation.
Remove duplicate tuples from the output.
Natural join: correct answers Output pairs of rows from the two input relations that have the
same value on all attributes that have the same name.
Cartesian product: correct answers Output all pairs of rows from the two input relations
(regardless of whether or not they have the same values on common attributes)
Union: correct answers Output the union of tuples from the two input relations.
