MC	Which statement is CORRECT?	Traditional relational databases allow for a certain measure of temporary inconsistency, in return for increased performance.	incorrect	Archiving is an approach in which database files are copied periodically to other storage media, such as tape or (another) hard disk. 	correct	The logfile contains all updates after they have been written to disk. 	incorrect	If the precedence graph contains a cycle, the schedule is serializable.	incorrect	
MC	Which statement is CORRECT?	Disk mirroring is a (near) real time approach that writes the same data simultaneously to two or more physical disks	correct	Multiple transactions may hold an exclusive lock on the same object.	incorrect	Traditional relational databases allow for a certain measure of temporary inconsistency, in return for increased performance.	incorrect	Transactions typically exist in isolation, and cannot be executed concurrently with other transactions on the same data.	incorrect	
MC	Which statement is CORRECT?	Multiple transactions may hold an exclusive lock on the same object.	incorrect	Multiple transactions may hold a shared lock on the same object.	correct	
MC	Which statement is CORRECT?	Archiving is an approach in which database files are copied periodically to other storage media, such as tape or (another) hard disk. 	correct	The lost update problem not always results in an inconsistent database state, whereas an uncommitted dependency or inconsistent analysis always yields an inconsistent database state.	incorrect	The Read committed isolation level uses long-term read locks, but short-term write locks. 	incorrect	A serial scheduler can be considered as an extreme case of a (very) optimistic scheduler.	incorrect	
MC	Which statement is NOT CORRECT?	The logfile contains all updates after they have been written to disk. 	correct	The logfile contains redundant data.	incorrect	The logfile can be implemented as a sequential file.	incorrect	The logfile is often duplicated, e.g. in a RAID level 1 configuration.	incorrect	
MC	Which statement is CORRECT?	Multiple transactions may hold an exclusive lock on the same object.	incorrect	Multiple transactions may hold a shared lock on the same object.	correct	
MC	Which statement is NOT CORRECT?	It should not be possible to terminate a transaction in such a way that the database remains in an inconsistent state, because some operations of a single transaction were executed successfully and others were not.	incorrect	Recovery is the activity of ensuring that, whichever problem occurred, the database is returned to a consistent state afterwards, without any data loss. 	incorrect	Transactions typically exist in isolation, and cannot be executed concurrently with other transactions on the same data.	correct	A transaction is a set of database operations (e.g. a consecution of SQL statements in a relational database), induced by a single user or application, that should be considered as one undividable unit of work.	incorrect	
MC	Which statement is NOT CORRECT?	With optimistic concurrency, locks are not used to limit simultaneity, but to detect conflicts during transaction execution, that will need to be resolved before transaction commit.	incorrect	A pessimistic protocol assumes it to be very likely that transactions will interfere and cause conflicts.	incorrect	An optimistic protocol assumes that conflicts between simultaneous transactions are exceptional.	incorrect	A serial scheduler can be considered as an extreme case of a (very) optimistic scheduler.	correct	
MC	Which statement is NOT CORRECT?	The inconsistent analysis problem denotes a situation where a transaction reads partial results of another transaction that simultaneously interacts with (and updates) the same data items. 	incorrect	The Read committed isolation level uses long-term read locks, but short-term write locks. 	correct	A transaction is a set of database operations (e.g. a consecution of SQL statements in a relational database), induced by a single user or application, that should be considered as one undividable unit of work.	incorrect	If the precedence graph contains a cycle, the schedule is not serializable.	incorrect	
MC	Which statement is CORRECT?	Multiple transactions may hold a shared lock on the same object.	correct	Multiple transactions may hold an exclusive lock on the same object.	incorrect