MC	Which statement is NOT CORRECT?	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	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	
MC	Which of the following DBMS components is involved in Transaction Management?	Scheduler	incorrect	Stored data manager	incorrect	Buffer manager	incorrect	Recovery manager	incorrect	All of these components	correct	
MC	When a transaction is aborted, it is important that:	A rollback of the transaction is executed: all changes made by the transaction's respective operations should be undone.	correct	All changes made by the individual operations belonging to that transaction should be made permanent.	incorrect	
MC	If the precedence graph contains a cycle, the schedule is...	not serializable	correct	serializable	incorrect	
MC	Which statement is NOT 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.	correct	Archiving is an approach in which database files are copied periodically to other storage media, such as tape or (another) hard disk. 	incorrect	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	The logfile contains redundant data.	incorrect	
MC	If the precedence graph contains a cycle, the schedule is...	not serializable	correct	serializable	incorrect	
MC	Which statement is NOT CORRECT?	If a transaction reads one or more data items that are being updated by another, as yet uncommitted, transaction, we may run into the uncommitted dependency problem. 	incorrect	A lost update problem occurs if an, otherwise successful, update of a data item by a transaction is overwritten by another transaction that wasn't 'aware' of the first update.	incorrect	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 lost update problem not always results in an inconsistent database state, whereas an uncommitted dependency or inconsistent analysis always yields an inconsistent database state.	correct	
MC	When a transaction is aborted, it is important that:	A rollback of the transaction is executed: all changes made by the transaction's respective operations should be undone.	correct	All changes made by the individual operations belonging to that transaction should be made permanent.	incorrect	
MC	According to the MGL-Protocol, 	locks are acquired bottom-up, but released top-down in the hierarchy.	incorrect	locks are acquired top-down, but released bottom-up in the hierarchy.	correct	
MC	Which statement is NOT CORRECT?	Disk mirroring is a (near) real time approach that writes the same data simultaneously to two or more physical disks	incorrect	There is a trade-off between the cost (overhead and storage cost) of more frequent backups and the cost of lost data because of less frequent backups.	incorrect	Archiving is an approach in which database files are copied periodically to other storage media, such as tape or (another) hard disk. 	incorrect	Traditional relational databases allow for a certain measure of temporary inconsistency, in return for increased performance.	correct