Question 1

In a network environment, a centralized database provides local autonomy over the data.

Accepted Answer

A) True 
 B)False  False

Question 2

Consider the following relational database for Grand Travel Airlines.
Grand Travel Airlines has to keep track of its flight and airplane history. A flight is uniquely identified by the combination of a flight number and a date. Every passenger who has flown on Grand Travel has a unique passenger number. For a particular passenger who has taken a particular flight, the company wants to keep track of the fare that she paid for it and the date that she made the reservation for it. Clearly, a passenger may have taken many flights (he must have taken at least one to be in the database) and every flight has had many passengers on it.
A pilot is identified by a unique pilot (or employee) number. A flight on a particular date has exactly one pilot. Each pilot has typically flown many flights but a pilot may be new to the company, is in training, and has not flown any flights, yet. Each airplane has a unique serial number. A flight on a particular date used one airplane. Each airplane has flown on many flights and dates, but a new airplane may not have been used at all, yet.
News flash!!! Grand Travel Airlines has decided to reconfigure its database as a distributed database among its four "hub" airport locations: Boston (which is also its headquarters city), Seattle, Nashville, and Columbus, Ohio.
Distributed and replicated among these four locations, the tables have the following characteristics:
Basically, all of these tables are accessed by all four locations on a fairly equal basis, except that processing at the Boston headquarters tends to be heavier than at the other three hubs. Replication is used primarily for availability purposes in case one of the sites crashes and the replicated copies are dispersed to avoid creating a bottleneck at any one site.
 $$\begin{array} { | l | l | l | l |} 
\hline \text { Pilot } & \text { Pilot } & \text { Date of } & \text { Date of } \
\text { Number } & \text { Narne } & \text { Birth } & \text { Hire } \
\hline
\end{array}$$ PILOT Relation
 $$\begin{array} { | l | l | l | l | l | l | } 
\hline \text { Flight } & & \text { Departure } & \text { Arrival } & \text { Pilot } & \text { Airplane } \
\text { Number } & \text { Date } & \text { Time } & \text { Time } & \text { Number } & \text { Number } \
\hline
\end{array}$$ FLIGHT Relation
 $$\begin{array} { | l | l | l | l | } 
\hline \text { Passenger } & \text { Passenger } & & \text { Telephone } \
\text { Number } & \text { Name } & \text { Address } & \text { Number } \
\hline
\end{array}$$ PASSENGER Relation
 $$\begin{array} { | l | l | l | l | l | } 
\hline \text { Flight } & & \text { Passenger } & & \text { Reservation } \
\text { Number } & \text { Date } & \text { Number } & \text { Fare } & \text { Date }\
\hline
\end{array}$$ RESERVATION Relation
 $$\begin{array} { | l | l | l | l | l | } 
\hline \text { Airplarne } & & \text { Passenger } & \text { Year } & \
\text { Number } & \text { Model } & \text { Capacity } & \text { Built } & \text { Marufacturer } \
\hline
\end{array}$$ AIRPLANE Relation
PILOT consists of 2,000 records and is located in Boston and Nashville.
FLIGHT consists of 1,500 records and is located in Columbus and Seattle.
PASSENGER consists of 250,000 records and is located in Columbus and Seattle.
RESERVATION consists of 1,500,000 and is located in Boston and Nashville.
AIRPLANE consists of 450 records and is located only at headquarters in Boston.
Assume that the telecommunications costs among the cities are all about the same.
Develop and justify a plan for solving the following queries. 
a. A query is issued from Nashville to list the names and addresses of the passengers who have reservations for a particular flight on a particular date one month from now.
b. A query is issued from Nashville to get a list of the serial number, model, and passenger capacity of the airplanes used on a particular flight (a flight that operates daily) during the last two months.
c. A query is issued from Boston to get a list of the serial number, model, and passenger capacity of the airplanes used on a particular flight (a flight that operates daily) during the last two months.

Accepted Answer

a. This query requires the PASSENGER and RESERVATION tables. The RESERVATION table is in Nashville, where the query was issued. Since there is only one flight involved and a passenger can have only one reservation on a given flight on a given date, the same number of records of the PASSENGER and RESERVATION tables will be involved. Clearly, the RESERVATION table in Nashville, where the query was issued, will be accessed first to find the passenger numbers of the passengers on the flight. That data will then be shipped to either Columbus or Seattle to get the passenger details and then the results will be sent back to Nashville.

b. In this case, neither of the two tables needed, AIRPLANE and FLIGHT are at the query-issuing city, Nashville. Furthermore, there is no single city on the network that has both tables. About sixty FLIGHT records are involved (one per day for two months) and then up to a maximum of sixty (but probably fewer) AIRPLANE records are involved. The best solution would be to start at the FLIGHT table in either Columbus or Seattle, pull the sixty flight records, get a list of the airplanes used on the flights, ship that information to Boston where the airplane detail data resides, and send the results back to Nashville.

c. This is the same situation as in query b above, except that the query is issued from Boston where the AIRPLANE table is located. Thus Boston can query the FLIGHT table in either Columbus or Seattle, pull the sixty flight records, bring them back to Boston, and complete the query on site.

Question 3

In the database server approach to client/server database, when a client computer on the LAN needs to query, update, or otherwise use a file on the server, the entire file must be sent from the server to that client.

Accepted Answer

A) True 
 B)False  False

Question 4

If the nature of the distributed replicated data and of the applications that use it can tolerate retrieved data not necessarily being up-to-the-minute accurate then a(n) ____ approach to updating replicated data can be used.

Accepted Answer

A)  mirrored 
B)  duplicated 
C)  synchronous 
D)  asynchronous 
E)  versioning 
A)  mirrored 
B)  duplicated 
C)  synchronous 
D)  asynchronous 
E)  versioning

Question 5

In a two-tiered client/server arrangement, data can be found on each PC's hard drive and data can be in a database at the server.

Accepted Answer

A) True 
 B)False

Question 6

If in a distributed database network, a copy of the entire database is kept at the headquarters site and each table is replicated exactly once at any one of the other sites, the application environment can continue to function even if the headquarters site goes down.

Accepted Answer

A) True 
 B)False

Question 7

The purpose of partitioning a table on a distributed network is to locate records of the table at sites at which they are most frequently used.

Accepted Answer

A) True 
 B)False

Question 8

A distributed join is never necessary ____.

Accepted Answer

A)  if distributed data is not replicated 
B)  if distributed data is replicated 
C)  if a copy of every table is kept at one site in a distributed database network 
D)  if there are at least two copies of every table in a distributed database network 
E)  if there are at least two copies of every table involved in the join in a distributed database network 
A)  if distributed data is not replicated 
B)  if distributed data is replicated 
C)  if a copy of every table is kept at one site in a distributed database network 
D)  if there are at least two copies of every table in a distributed database network 
E)  if there are at least two copies of every table involved in the join in a distributed database network

Question 9

All of the following are true of a centralized database on a network, except ____.

Accepted Answer

A)  the site with the database can become a bottleneck 
B)  there is no need for a distributed directory since all of the data is in one place 
C)  the single site arrangement provides a high degree of security, concurrency, and backup and recovery control 
D)  all data accesses from other than the site with the database incur telecommunications costs 
E)  it uses a two-phase commit process 
A)  the site with the database can become a bottleneck 
B)  there is no need for a distributed directory since all of the data is in one place 
C)  the single site arrangement provides a high degree of security, concurrency, and backup and recovery control 
D)  all data accesses from other than the site with the database incur telecommunications costs 
E)  it uses a two-phase commit process

Question 10

The two phases of the two-phase commit process are ____ and commit.

Accepted Answer

A)  copy 
B)  prepare 
C)  de-commit 
D)  replicate 
E)  concur 
A)  copy 
B)  prepare 
C)  de-commit 
D)  replicate 
E)  concur

Question 11

Compared to the file server approach, the database server approach to client/server database _____.

Accepted Answer

A)  generates more network data traffic 
B)  requires more processing power at the server 
C)  requires a gateway connection to a mainframe computer 
D)  spreads security control through all of the client PCs 
E)  requires "fatter" client PCs with more processing power 
A)  generates more network data traffic 
B)  requires more processing power at the server 
C)  requires a gateway connection to a mainframe computer 
D)  spreads security control through all of the client PCs 
E)  requires "fatter" client PCs with more processing power

Question 12

The two-phase commit process can be used when the ____ approach to updating distributed replicated data is required.

Accepted Answer

A)  mirrored 
B)  duplicated 
C)  synchronous 
D)  asynchronous 
E)  versioning 
A)  mirrored 
B)  duplicated 
C)  synchronous 
D)  asynchronous 
E)  versioning

Question 13

The two-phase commit process is used for replicated data that can tolerate having its table copies not being up-to-date all of the time.

Accepted Answer

A) True 
 B)False

Question 14

In one use of the term three-tier approach to client/server database the three tiers are the client PCs, servers known as "application servers" and other servers known as "database servers."

Accepted Answer

A) True 
 B)False

Question 15

Horizontal partitioning is advisable on a distributed database network ____.

Accepted Answer

A)  when particular records of a table are used at some network sites more than at others 
B)  when all records of a table are used at some network sites more than at others 
C)  when different sites on the network require different columns of the table 
D)  when all of the columns of a table are used at some network sites more than at others 
E)  None of the above. 
A)  when particular records of a table are used at some network sites more than at others 
B)  when all records of a table are used at some network sites more than at others 
C)  when different sites on the network require different columns of the table 
D)  when all of the columns of a table are used at some network sites more than at others 
E)  None of the above.

Question 16

The commit phase is the first phase of the two-phase commit process.

Accepted Answer

A) True 
 B)False

Question 17

One use of the term three-tier approach to client/server database is that data sought from one of the client PCs can be on any one of a succession of three other PCs on the LAN.

Accepted Answer

A) True 
 B)False

Question 18

Partitioned tables in a distributed database network tend to decrease local autonomy over data.

Accepted Answer

A) True 
 B)False

Question 19

All of the following are principles of data replication in a distributed database network, except ____.

Accepted Answer

A)  place a copy of every table at a central node to avoid having a bottleneck 
B)  place copies of tables at the sites that use them most heavily in order to minimize telecommunications costs 
C)  ensure that there are at least two copies of important or frequently used tables to realize the gains in availability 
D)  limit the number of copies of any one table to control the security and concurrency issues 
E)  avoid any one site becoming a bottleneck to maintain performance 
A)  place a copy of every table at a central node to avoid having a bottleneck 
B)  place copies of tables at the sites that use them most heavily in order to minimize telecommunications costs 
C)  ensure that there are at least two copies of important or frequently used tables to realize the gains in availability 
D)  limit the number of copies of any one table to control the security and concurrency issues 
E)  avoid any one site becoming a bottleneck to maintain performance

Question 20

In a three-tier approach to client/server database ____.

Accepted Answer

A)  three of the client PCs on a LAN each constitute a tier 
B)  three LANs connected through gateway computers each constitute a tier 
C)  data location transparency runs through all three tiers 
D)  data can be stored at the tiers in the LAN but not at the one outside of it 
E)  the file server approach rather than the database server approach must be used 
A)  three of the client PCs on a LAN each constitute a tier 
B)  three LANs connected through gateway computers each constitute a tier 
C)  data location transparency runs through all three tiers 
D)  data can be stored at the tiers in the LAN but not at the one outside of it 
E)  the file server approach rather than the database server approach must be used

In a network environment, a centralized database provides local autonomy over the data.

In the database server approach to client/server database, when a client computer on the LAN needs to query, update, or otherwise use a file on the server, the entire file must be sent from the server to that client.

If the nature of the distributed replicated data and of the applications that use it can tolerate retrieved data not necessarily being up-to-the-minute accurate then a(n) ____ approach to updating replicated data can be used.

In a two-tiered client/server arrangement, data can be found on each PC's hard drive and data can be in a database at the server.

If in a distributed database network, a copy of the entire database is kept at the headquarters site and each table is replicated exactly once at any one of the other sites, the application environment can continue to function even if the headquarters site goes down.

The purpose of partitioning a table on a distributed network is to locate records of the table at sites at which they are most frequently used.

A distributed join is never necessary ____.

All of the following are true of a centralized database on a network, except ____.

The two phases of the two-phase commit process are ____ and commit.

Compared to the file server approach, the database server approach to client/server database _____.

The two-phase commit process can be used when the ____ approach to updating distributed replicated data is required.

The two-phase commit process is used for replicated data that can tolerate having its table copies not being up-to-date all of the time.

In one use of the term three-tier approach to client/server database the three tiers are the client PCs, servers known as "application servers" and other servers known as "database servers."

Horizontal partitioning is advisable on a distributed database network ____.

The commit phase is the first phase of the two-phase commit process.

One use of the term three-tier approach to client/server database is that data sought from one of the client PCs can be on any one of a succession of three other PCs on the LAN.

Partitioned tables in a distributed database network tend to decrease local autonomy over data.

All of the following are principles of data replication in a distributed database network, except ____.

In a three-tier approach to client/server database ____.

Data: the New Corporate Resource

Data Modeling

The Database Management System Concept

Relational Data Retrieval: SQL

The Relational Database Model: Introduction

The Relational Database Model: Additional Concepts

Logical Database Design

Physical Database Design

Object-Oriented Database Management

Data Administration, Database Administration, and Data Dictionaries

Database Control Issues: Security, Backup and Recovery, Concurrency

The Data Warehouse

Database and the Internet

Filters

Exam 12: Clientserver Database and Distributed Database

In a network environment, a centralized database provides local autonomy over the data.

In the database server approach to client/server database, when a client computer on the LAN needs to query, update, or otherwise use a file on the server, the entire file must be sent from the server to that client.

If the nature of the distributed replicated data and of the applications that use it can tolerate retrieved data not necessarily being up-to-the-minute accurate then a(n) ____ approach to updating replicated data can be used.

In a two-tiered client/server arrangement, data can be found on each PC's hard drive and data can be in a database at the server.

If in a distributed database network, a copy of the entire database is kept at the headquarters site and each table is replicated exactly once at any one of the other sites, the application environment can continue to function even if the headquarters site goes down.

The purpose of partitioning a table on a distributed network is to locate records of the table at sites at which they are most frequently used.

A distributed join is never necessary ____.

All of the following are true of a centralized database on a network, except ____.

The two phases of the two-phase commit process are ____ and commit.

Compared to the file server approach, the database server approach to client/server database _____.

The two-phase commit process can be used when the ____ approach to updating distributed replicated data is required.

The two-phase commit process is used for replicated data that can tolerate having its table copies not being up-to-date all of the time.

In one use of the term three-tier approach to client/server database the three tiers are the client PCs, servers known as "application servers" and other servers known as "database servers."

Horizontal partitioning is advisable on a distributed database network ____.

The commit phase is the first phase of the two-phase commit process.

One use of the term three-tier approach to client/server database is that data sought from one of the client PCs can be on any one of a succession of three other PCs on the LAN.

Partitioned tables in a distributed database network tend to decrease local autonomy over data.

All of the following are principles of data replication in a distributed database network, except ____.

In a three-tier approach to client/server database ____.

Data: the New Corporate Resource

Data Modeling

The Database Management System Concept

Relational Data Retrieval: SQL

The Relational Database Model: Introduction

The Relational Database Model: Additional Concepts

Logical Database Design

Physical Database Design

Object-Oriented Database Management

Data Administration, Database Administration, and Data Dictionaries

Database Control Issues: Security, Backup and Recovery, Concurrency

The Data Warehouse

Database and the Internet

Filters