Q&A Hero

Q: A system table space, a user data table space, an index table space, and a temporary table space are examples of _____.a. procedure cachesb. file groupsc. data cachesd. operation modes

Q: A(n)___________ is a logical grouping of several data files that store data with similar characteristics.a. procedure cacheb. table spacec. data cached. listener

Q: A DBA determines the initial size of the data files that make up the database; however, as required, the data files can automatically expand in predefined increments known as_______ .a. procedure cacheb. buffer cachec. supplementsd. extends

Q: When moving data from permanent storage to RAM, an I/O disk operation retrieves:a. an entire table.b. an entire physical disk block.c. only the row containing the attribute requested.d. only the attribute which was requested.

Q: On the server side, the database environment must be properly configured to respond to clients' requests in the fastest way possible, while making optimum use of existing resources. The activities required to achieve this goal are commonly referred to as___________ tuning.a. client and serverb. database SQLc. SQL performanced. DBMS performance

Q: On the client side, the objective is to generate an SQL query that returns a correct answer in the least amount of time, using a minimum amount of resources at the server end. The activities required to achieve this goal are commonly referred to as __________tuning.a. client SQLb. database SQLc. SQL performanced. DBMS performance

Q: DBMS performance tuning includes global tasks such as managing the DBMS processes in primary memory and managing the structures in physical storage. a. True b. False

Q: In-memory database systems are optimized to store small portions of the database in disk storage alone. a. True b. False

Q: RAID systems use a single disk to create storage volumes. a. True b. False

Q: Maximizing disk contention is one of the general recommendations for the physical storage of databases. a. True b. False

Q: Character field comparisons are faster than numeric, date, and NULL comparisons. a. True b. False

Q: Indexes are very useful in small tables or tables with low sparsity. a. True b. False

Q: Most current-generation relational DBMSs perform automatic query optimization at the client end.a. Trueb. False

Q: A cost-based optimizer uses a set of preset rules and points to determine the best approach to execute a query. a. True b. False

Q: The primary factor in determining the most efficient access plan is the I/O cost. a. True b. False

Q: Using index characteristics, a database designer can determine the best type of index to use. a. True b. False

Q: Indexes do not facilitate join operations. a. True b. False

Q: An index scan is less efficient than a full table scan. a. True b. False

Q: All transaction management commands are processed during the parsing and execution phases of query processing. a. True b. False

Q: The SQL execution activities are performed by the query optimizer. a. True b. False

Q: Fully equivalent means that the optimized query results are always the same as the original query. a. True b. False

Q: Working with data in the data cache is many times faster than working with data in the data files. a. True b. False

Q: The purpose of an I/O operation is to move data to and from different computer components or devices. a. True b. False

Q: To work with data, the DBMS must retrieve the data from permanent storage and place it in RAM. a. True b. False

Q: The SQL cache stores the end-user written SQL. a. True b. False

Q: The data cache caches system catalog data and the contents of the indexes. a. True b. False

Q: A data file can contain rows from a single table alone. a. True b. False

Q: DBMS implementations are typically similar in complexity to two-tier client/server configurations. a. True b. False

Q: Good database performance starts with good database design. a. True b. False

Q: All factors must be checked to ensure that each system component operates at its optimum level and has sufficient resources to minimize the occurrence of bottlenecks. a. True b. False

Q: Good database performance is easy to evaluate. a. True b. False

Q: One of the main functions of a database system is to provide timely answers to end users. a. True b. False

Q: How do transaction recovery procedures use the deferred-write and write-through techniques to recover transactions?

Q: What are database checkpoints?

Q: What are the three basic techniques to control deadlocks?

Q: How does a shared/exclusive lock schema increase the lock manager's overhead?

Q: Explain the transaction log. What is its function?

Q: What is transaction isolation and why it is important?

Q: Database transaction_____________ restores a database from an inconsistent state to a previously consistent state.

Q: ____________ensure that a disk physical failure will not impair the DBMS's ability to recover data.

Q: In a heavily used database management system (DBMS), the prevention and detection of________ constitutes an important DBMS function.

Q: Uniqueness ensures that no equal time stamp values can exist, and__________ ensures that time stamp values always increase.

Q: If T1 has not unlocked data item Y, T2 cannot begin; if T2 has not unlocked data item X, T1 cannot continue. Consequently, T1 and T2 each wait for the other to unlock the required data item. Such a deadlock is also known as a(n) _____.

Q: The____________ rule states that only one transaction at a time can own an exclusive lock on the same object.

Q: As a rule, a(n)____________ must unlock the object after its termination.

Q: ______________-level locks are less restrictive than database-level locks, but they create traffic jams when many transactions are waiting to access the same table.

Q: ___________________can take place at any of the following levels: database, table, page, row, or field.

Q: Most multiuser_______________ automatically initiate and enforce locking procedures, where all locking information is managed by the lock manager.

Q: The _______________occurs when two concurrent transactions, T1 and T2, are updating the same data element and one of the updates is lost.

Q: To determine the appropriate order of the operations, the scheduler bases its actions on concurrency control algorithms, such as___________ or time stamping methods.

Q: The_______________ interleaves the execution of database operations to ensure serializability.

Q: The scheduler's main job is to create a(n) _______________of a transaction's operation, in which the interleaved executions of transactions yield the same results as if the transactions were executed in serial order.

Q: _______________control is important because the simultaneous execution of transactions over a shared database can create several data integrity and consistency problems.

Q: The objective of _____________control is to ensure the serializability of transactions in a multiuser database environment.

Q: If a(n)_____________ is issued before the termination of a transaction, the DBMS will restore the database only for that particular transaction, rather than for all transactions, in order to maintain the durability of the previous transactions.

Q: Although the DBMS is designed to recover a database to a previous consistent state when an interruption prevents the completion of a required set of transactions, the transactions themselves are defined by the end user or programmer and must be correct.

Q: A(n)____________ occurs when a transaction executes a query at time t1, and then it runs the same query at time t2, yielding additional rows that satisfy the query.a. phantom readb. dirty readc. uncommitted dependencyd. nonrepeatable read

Q: The__________ isolation level ensures that queries return consistent results.a. Read Uncommittedb. Read Committedc. Serializabled. Repeatable Read

Q: In the optimistic approach, during the _________phase, changes are permanently applied to the database.a. readb. validationc. writed. shared

Q: In the optimistic approach, during the____________ phase, a transaction scans the database, executes the needed computations, and makes the updates to a private copy of the database values.a. readb. validationc. writed. shared

Q: The________ approach to scheduling concurrent transactions assigns a global unique stamp to each transaction.a. scheduledb. table-lockingc. uniqued. timestamping

Q: In the wait/die scheme,:a. the older transaction rolls back the younger transaction and reschedules it.b. the younger, preempted transaction is rescheduled using the same time stamp.c. the older transaction waits for the younger one to complete and release its locks.d. both the younger and older transactions wait indefinitely to be released.

Q: A(n)_________ condition occurs when two or more transactions wait for each other to unlock data.a. deadlockb. exclusive lockc. binary lockd. two-phase lock

Q: A__________ occurs when two or more transactions wait for each other to unlock data.a. livelockb. database deadlockc. distributed deadlockd. phantom deadlocks

Q: A(n) _____________phase in a two-phase lock is when a transaction releases all locks and cannot obtain any new lock.a. growingb. shrinkingc. lockingd. unlocking

Q: What is a rule that applies to the two-phase locking protocol? a. Two transactions cannot have conflicting locks. b. No unlock operation can precede a lock operation in a different transaction. c. No data is affected until all locks are release d. d. No data is affected until the transaction is in its locked position.

Q: A(n)___________ lock exists when concurrent transactions are granted read access on the basis of a common lock.a. sharedb. exclusivec. binaryd. two-phase

Q: A(n)_________ specifically reserves access to the transaction that locked the object.a. shared lockb. exclusive lockc. binary lockd. deadlock

Q: A(n)_________ lock has only two stages (0 and 1).a. sharedb. exclusivec. binaryd. two-phase

Q: A ___________lock allows concurrent transactions to access different rows of the same table.a. database-levelb. table-levelc. page-leveld. row-level

Q: A diskpage, or page, is the equivalent of a____________ .a. database tableb. disk sectorc. database schemad. diskblock

Q: A_________ lock locks the entire diskpage.a. transaction-levelb. table-levelc. page-leveld. row-level

Q: A__________ lock locks the entire table preventing access to any row by a transaction while another transaction is using the table.a. database-levelb. table-levelc. page-leveld. row-level

Q: Lock___________ indicates the level of lock use.a. granularityb. shrinkingc. growingd. serializability

Q: The_________ manager is responsible for assigning and policing the locks used by the transactions.a. transactionb. databasec. lockd. schedule

Q: ____________are required to prevent another transaction from reading inconsistent data.a. Locksb. Schedulesc. Stampsd. Logs

Q: A __________lock prevents the use of any tables in the database from one transaction while another transaction is being processed.a. database-levelb. table-levelc. page-leveld. row-level

Q: As long as two transactions, T1 and T2, access _________data, there is no conflict, and the order of execution is irrelevant to the final outcome.a. sharedb. commonc. unrelatedd. locked

Q: ______________occurs when a transaction accesses data before and after one or more other transactions finish working with such data.a. Inconsistent retrievalsb. The phenomena of uncommitted datac. Lost update problemsd. Dirty read problems

Q: One of the three most common data integrity and consistency problems is______________ .a. lost updatesb. disk failuresc. user errorsd. deadlocks