Database Concepts, 7e (Kroenke/Auer)
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Chapter 6 Database Administration
1) Only large database systems have a need for database administration.
Answer: FALSE
Diff: 1 Page Ref: 335
2) The acronym DBA refers to either the office or the manager.
Answer: TRUE
Diff: 1 Page Ref: 336
3) The purpose of concurrency control is to ensure that one user's work does not inappropriately influence another user's work.
Answer: TRUE
Diff: 2 Page Ref: 338
4) All actions in an atomic transaction are completed successfully or none of the actions are completed at all.
Answer: TRUE
Diff: 1 Page Ref: 338
5) A transaction in which all steps must be completed successfully or none of them will be completed is called a durable transaction.
Answer: FALSE
Diff: 2 Page Ref: 338
6) Concurrent processing of a database only poses problems when two or more processes attempt to use the same data.
Answer: TRUE
Diff: 3 Page Ref: 339-340
7) A dirty read is a problem with concurrent processing when a transaction rereads data it has
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already read and finds modifications or deletions caused by another transaction.
Answer: FALSE
Diff: 3 Page Ref: 341
8) One way to prevent concurrent processing problems is to lock data that are retrieved for update.
Answer: TRUE
Diff: 1 Page Ref: 341
9) Lock granularity refers to whether a lock is placed by the DBMS automatically or is placed by a command from the application program.
Answer: FALSE
Diff: 1 Page Ref: 341-342
10) Two-phase locking can be used to ensure that transactions are serializable.
Answer: TRUE
Diff: 2 Page Ref: 342
11) With optimistic locking, locks are first issued, then the transaction is processed, and then the locks are released.
Answer: FALSE
Diff: 3 Page Ref: 342-344
12) One advantage of optimistic locking is that the lock is obtained only after the transaction is processed.
Answer: TRUE
Diff: 2 Page Ref: 342-344
13) Statement level consistency means that all statements within a transaction will access consistent rows across the lifetime of the entire transaction.
Answer: FALSE
Diff: 3 Page Ref: 346-347
14) Generally, the more restrictive the transaction isolation level, the less the throughput of database processing.
Answer: TRUE
Diff: 2 Page Ref: 347-348
15) Database security is easy to achieve since all security is handled by the DBMS, which is a single point of entry into the database.
Answer: FALSE
Diff: 2 Page Ref: 350
16) In terms of database security, a user can be assigned many roles, and a role can be assigned to many users.
Answer: TRUE
Diff: 3 Page Ref: 351-352
17) The simplest and most feasible means of recovering a database is through reprocessing.
Answer: FALSE
Diff: 2 Page Ref: 357
18) In comparison to reprocessing, rollforward does not involve the application programs.
Answer: TRUE
Diff: 3 Page Ref: 358-361
19) Rollback requires the use of logs, but rollforward does not.
Answer: FALSE
Diff: 1 Page Ref: 358-360
20) Transactions should be written to the log before they are applied to the database itself.
Answer: TRUE
Diff: 2 Page Ref: 358-361
21) Microsoft Access 2013 uses a user-level security system.
Answer: FALSE
Diff: 2 Page Ref: 361
22) Microsoft Access 2013 databases can be secured using trusted locations for database storage.
Answer: TRUE
Diff: 2 Page Ref: 362-363
23) Microsoft Access 2013 databases cannot be secured by password encryption.
Answer: FALSE
Diff: 2 Page Ref: 369
24) Microsoft Access 2013 databases can be secured by deploying databases packaged with digital signatures.
Answer: TRUE
Diff: 2 Page Ref: 376
25) When Microsoft Access 2013 uses user-level security with an Access 2003 file, the database is stored in a(n) *.accdb file.
Answer: FALSE
Diff: 1 Page Ref: 381
26) The term DBA refers to the:
A) database accessor.
B) database auditor.
C) data business auditor.
D) database administrator.
E) data business administrator.
Answer: D
Diff: 1 Page Ref: 336
27) Which of the following is not a means of processing databases?
A) Internet applications using ASP
B) Internet applications using JSP
C) Applications invoking stored procedures
D) Programs coded in C#
E) All of the above are means of processing a database.
Answer: E
Diff: 2 Page Ref: 336-338
28) The purpose of concurrency control is to:
A) ensure that each form has a corresponding report.
B) ensure that ASPs do not duplicate JSPs.
C) ensure that one user's work does not interfere with another's.
D) ensure that stored procedures do not invoke triggers.
E) ensure that triggers do not invoke stored procedures.
Answer: C
Diff: 1 Page Ref: 338
29) When a transaction functions in such a way that either all of the transaction actions are completed or none of them will be, the transaction is said to be:
A) consistent.
B) isolated.
C) atomic.
D) locked.
E) logical.
Answer: C
Diff: 2 Page Ref: 338
30) What concurrent processing problem occurs when a transaction rereads data and finds new rows that were inserted by a different transaction since the prior read?
A) Nonrepeatable reads
B) Phantom reads
C) Dirty reads
D) Serialized reads
E) Unlocked reads
Answer: B
Diff: 2 Page Ref: 347
31) What concurrent processing problem occurs when a transaction reads a changed record that has not been committed to the database?
A) Nonrepeatable reads
B) Phantom reads
C) Dirty reads
D) Serialized reads
E) Unlocked reads
Answer: C
Diff: 2 Page Ref: 347
32) Preventing multiple applications from obtaining copies of the same record when the record is about to be changed is called:
A) serialized reading.
B) lost updating.
C) concurrent processing.
D) resource locking.
E) block factoring.
Answer: D
Diff: 1 Page Ref: 341
33) Whether a lock applies to data at the record level, page level, table level, or database level is referred to as:
A) lock exclusivity.
B) lock sharing.
C) lock phasing.
D) serializable locking.
E) lock granularity.
Answer: E
Diff: 2 Page Ref: 341-342
34) Which of the following is true about a shared lock?
A) It is more restrictive than an implicit lock.
B) It allows only two transactions to update a record simultaneously.
C) It locks the item from all access.
D) It allows reads to the locked item.
E) It must use a two-phase locking scheme.
Answer: D
Diff: 3 Page Ref: 341-342
35) Which type of lock assumes that no conflicts will occur?
A) Optimistic locks
B) Granular locks
C) Explicit locks
D) Shared locks
E) Open locks
Answer: A
Diff: 1 Page Ref: 342-344
36) An ACID transaction is one that is:
A) atomic.
B) consistent.
C) isolated.
D) durable.
E) All of the above
Answer: E
Diff: 1 Page Ref: 346-347
37) Ensuring that each SQL statement independently processes consistent rows is known as:
A) transaction level consistency.
B) independent consistency.
C) statement level consistency.
D) process level consistency.
E) serializable consistency.
Answer: C
Diff: 2 Page Ref: 346-347
38) What is the least restrictive isolation level that will prevent phantom read problems?
A) Read Committed
B) Serializable
C) Read Uncommitted
D) Atomic Read
E) Repeatable Read
Answer: B
Diff: 3 Page Ref: 347-348
39) What is the least restrictive isolation level that will prevent dirty reads?
A) Read Committed
B) Serializable
C) Read Uncommitted
D) Atomic Read
E) Repeatable Read
Answer: A
Diff: 3 Page Ref: 347-348
40) What is the least restrictive isolation level that will prevent nonrepeatable reads?
A) Read Committed
B) Serializable
C) Read Uncommitted
D) Atomic Read
E) Repeatable Read
Answer: E
Diff: 2 Page Ref: 347-348
41) Which of the following is not true of database recovery through reprocessing?
A) Reprocessing makes use of a database save.
B) Reprocessing takes the same amount of time as did processing in the first place.
C) Reprocessing will always return the database to its exact previous state.
D) Reprocessing requires a record of all transactions since the last time the database was saved.
E) All of the above are true of reprocessing.
Answer: C
Diff: 3 Page Ref: 357-358
42) The recovery technique in which the database is returned to a known state and then all valid transactions are reapplied to the database is known as:
A) reprocessing.
B) rollback.
C) transaction logging.
D) rollforward.
E) checkpointing.
Answer: D
Diff: 2 Page Ref: 358-360
43) A point of synchronization between the database and the transaction log is called a(n):
A) before-image.
B) after-image.
C) recovery.
D) checkpoint.
E) None of the above
Answer: D
Diff: 2 Page Ref: 358-360
44) Additional DBA responsibilities include:
A) problem and error reporting.
B) requests of changes to existing systems.
C) controlling database configuration.
D) maintaining appropriate documentation.
E) All of the above
Answer: E
Diff: 1 Page Ref: 361
45) Computer systems fail for which of the following reasons?
A) Hardware breaks.
B) Electrical power fails.
C) Programs have bugs.
D) People make mistakes.
E) All of the above
Answer: E
Diff: 1 Page Ref: 361
46) When Microsoft Access 2013 secures a database just by storing the database in a trusted location, the database file will be a(n):
A) *.accdb file.
B) *.accdc file.
C) *.accde file.
D) *.mdb file.
E) *.mdw file.
Answer: A
Diff: 2 Page Ref: 362-369
47) When Microsoft Access 2013 secures a database with just a password, the database file will be a(n):
A) *.accdb file.
B) *.accdc file.
C) *.accde file.
D) *.mdb file.
E) *.mdw file.
Answer: A
Diff: 2 Page Ref: 369-373
48) When Microsoft Access 2013 compiles VBA code in a database, the database file will be a(n):
A) *.accdb file.
B) *.accdc file.
C) *.accde file.
D) *.mdb file.
E) *.mdw file.
Answer: C
Diff: 2 Page Ref: 373-376
49) When Microsoft Access 2013 creates a signed package with a digital signature, the database file will be a(n):
A) *.accdb file.
B) *.accdc file.
C) *.accde file.
D) *.mdb file.
E) *.mdw file.
Answer: B
Diff: 2 Page Ref: 376-381
50) When Microsoft Access 2013 uses user-level security with an Access 2003 file, the database is stored in a(n):
A) *.accdb file.
B) *.accdc file.
C) *.accde file.
D) *.mdb file.
E) *.mdw file.
Answer: D
Diff: 2 Page Ref: 381
51) ________ is an important business function whose purpose is to manage the database to maximize its value to the organization.
Answer: Database administration
Diff: 2 Page Ref: 335-336
52) One of the major tasks of the database administration is called ________ control, which allows multiple users to access the database simultaneously.
Answer: concurrency
Diff: 2 Page Ref: 335-336
53) Database administrators must make sure that ________ measures are in place and enforced so that only authorized users can take authorized actions at appropriate times.
Answer: security
Diff: 2 Page Ref: 336
54) Database administrators must make sure that ________ and ________ techniques and procedures are operating to protect the database in case of failure and to recover it as quickly and accurately as possible when necessary.
Answer: backup; recovery
Diff: 2 Page Ref: 336
55) Serializable transactions are created by having a(n) ________ phase, in which locks are obtained, and a(n) ________ phase, in which locks are released.
Answer: growing; shrinking
Diff: 3 Page Ref: 342
56) Standard SQL defines four ________, which specify which of the concurrency control problems are allowed to occur.
Answer: isolation levels
Diff: 2 Page Ref: 347
57) Transaction results are kept in a(n) ________, which contains records of the data changes in chronological order.
Answer: log
Diff: 1 Page Ref: 357-360
58) The recovery method where the database is restored using the saved data, and all transactions since the save are reapplied is called ________ recovery.
Answer: rollforward
Diff: 2 Page Ref: 357-360
59) The recovery method in which we undo the changes that erroneous or partially processed transactions have made in the database is called ________ recovery.
Answer: rollback
Diff: 2 Page Ref: 357-360
60) Breaking hardware, power outages, and human mistakes are all reasons that ________.
Answer: computers fail
Diff: 2 Page Ref: 357
61) Microsoft Access 2013 can secure database files by storing them in a(n) ________.
Answer: trusted location
Diff: 2 Page Ref: 362
62) Microsoft Access 2013 can secure databases by using ________ to encrypt and decrypt the database files.
Answer: passwords
Diff: 3 Page Ref: 362
63) Microsoft Access 2013 can secure databases by deploying databases packaged with a(n) ________.
Answer: digital signature
Diff: 2 Page Ref: 362
64) When Microsoft Access 2013 compiles VBA code in a database, the resulting file is stored using a(n) ________ file extension.
Answer: *.accde
Diff: 2 Page Ref: 373
65) When Microsoft Access 2013 uses user-level security with an Access 2003 database file, it stores the database in a(n) ________ file.
Answer: *.mdb
Diff: 2 Page Ref: 381
66) What database administration functions help bring order to the potential chaos of the database processing environment?
Answer: First, the actions of concurrent users must be controlled so that consistent results are obtained. Second, security measures are necessary so that only authentic users who are properly authorized are permitted to take appropriate actions on databases. Finally, backup and recovery techniques and procedures must be in place to protect databases and the data they contain.
Diff: 1 Page Ref: 335-336
67) Explain the concept of an "atomic transaction."
Answer: An atomic transaction is a transaction in which either all steps must be completed successfully, or none of the steps can be completed at all. A transaction becomes atomic when the complete set of steps within the transaction is a single logical unit of work.
Diff: 1 Page Ref: 338
68) Briefly explain the strategy of two-phased locking.
Answer: Two-phased locking is a strategy to ensure the serializability of transactions. A transaction is allowed to obtain locks as necessary, but once the first lock is released, no other locks may be obtained. This produces the two-phased effect–the growing phase in which locks are obtained and the shrinking phase as locks are released.
Diff: 2 Page Ref: 342
69) Briefly define the three problems that can occur because of concurrent processing that are addressed by resource locking.
Answer: The three problems that can occur because of concurrent processing are dirty reads, nonrepeatable reads, and phantom reads. A dirty read occurs when a transaction reads a changed record that has not been committed to the database. If the change is cancelled before it is committed, then the read will contain incorrect data. A nonrepeatable read occurs when a transaction rereads data and finds modifications or deletions caused by another transaction. A phantom read occurs when a transaction rereads data and finds new rows that were inserted by another transaction since the prior read.
Diff: 2 Page Ref: 347
70) Explain the process of using optimistic locking.
Answer: Optimistic locking makes the assumption that no conflicts will occur. Data is read, the transaction is processed, updates are issued, and then a check is made to see if a conflict occurred. If a conflict does occur, the transaction is repeated until it completes without a conflict. Thus, the lock is not secured until the transaction is completed. This reduces the amount of time that the lock is held.
Diff: 2 Page Ref: 342-344
71) Distinguish between statement-level consistency and transaction-level consistency.
Answer: Statement-level consistency requires that a statement apply to a set of rows that is consistent from the beginning of the statement until the end of the statement. Transaction-level consistency indicates that the set of rows will remain consistent throughout the processing of all statements within the transaction.
Diff: 2 Page Ref: 346-347
72) What are the four transaction isolation levels?
Answer: The four levels of isolation are Read Uncommitted, Read Committed, Repeatable Read, and Serializable. Read Uncommitted is the least restrictive, and it produces reads that are susceptible to dirty reads, nonrepeatable reads, and phantom reads. Read Committed isolation prevents dirty reads by only reading committed changes. Repeatable Read isolation prevents dirty reads and nonrepeatable reads. Serializable is the most restrictive level of isolation, and it prevents dirty reads, nonrepeatable reads, and phantom reads.
Diff: 3 Page Ref: 347-348
73) What is the difference between authentication and authorization?
Answer: Authentication refers to making sure a user has the right to use the computer system in the first place. It is the precursor to authorization, which is assigning an authenticated user permission to perform specific tasks on the system. Both are needed for effective computer system security.
Diff: 2 Page Ref: 350
74) Why do computers fail?
Answer: Computers fail for a variety of reasons, including (1) hardware failure, (2) electrical power outages, (3) bugs in computer programs, (4) errors in procedures, and (5) human error.
Diff: 2 Page Ref: 357
75) Distinguish between reprocessing and rollforward as database recovery techniques.
Answer: Reprocessing and rollforward both require the use of database saves, which are backups of the database at a known state. Reprocessing as a means of recovery involves recovering the database from the last database save and having the application programs reprocess all the transactions since the save. Rollforward as a means of recovery involves recovering the database from the last save and then reapplying all changes to the database. Reprocessing does not always reproduce the original database contents correctly since minute changes in processing by the application programs may result in changes in data manipulation.
Diff: 3 Page Ref: 358-360
76) Discuss Microsoft Access 2013 security administration.
Answer: Microsoft Access 2013 files can be secured using three methods: (1) by creating trusted locations for file storage, (2) by password encryption and decryption of database files, and (3) by deploying databases packaged with a digital signature. Additionally, Microsoft Access 2013 can compile VBA code used with an Access 2013 database file. Finally Microsoft Access 2013 can still use user-level security for older *.mdb database files (but not for Access 2013 *.accdb files).
Diff: 3 Page Ref: 361-381
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