MC	Which statement is CORRECT?	With distributed 2PL, every site has its own lock manager, which is responsible for managing all locking data pertaining to the fragments stored on that site. 	correct	Even if the database contains replicated data, applying the basic 2PL protocol still suffices to guarantee serializability. 	incorrect	With a shared disk architecture, each processor has its own central storage but shares secondary storage with the other processors. 	incorrect	Optimistic concurrency may considerably increase transaction throughput and overall data availability in a tightly coupled setting.	incorrect	
MC	Optimistic concurrency may considerably increase transaction throughput and overall data availability in a...	tightly coupled setting.	incorrect	loosely coupled setting.	correct	
MC	Which statement is CORRECT?	With horizontal fragmentation, each fragment consists of a subset of the columns of the global data set.	incorrect	With BASE transactions, conflict resolution always happens at the moment of writing the data.	incorrect	Location transparency means that database users do not need to know on which node the required data resides.	correct	Many NoSQL databases apply some form of vertical fragmentation.	incorrect	
MC	Which statement is CORRECT?	A schedule in 2PL is deadlock free if the local wait-for graph contains only a limited number of cycles.	incorrect	Optimistic concurrency may considerably increase transaction throughput and overall data availability in a loosely coupled setting.	correct	Eventual consistency in a NoSQL environment implies that the database is consistent at all times.	incorrect	Even if the database contains replicated data, applying the basic 2PL protocol still suffices to guarantee serializability. 	incorrect	
MC	Many NoSQL databases apply some form of...	horizontal fragmentation.	correct	vertical fragmentation.	incorrect	
MC	Which statement is NOT CORRECT?	Replication transparency means that different replicas of the same data item will be automatically kept consistent by the database system and updates to one replica will be propagated transparently (be it synchronously or asynchronously) to the other copies of the same data item.	incorrect	Transaction transparency refers to the fact that the distributed database can be accessed and queried in a uniform fashion, regardless of the different database systems and APIs that may be involved. 	correct	Location transparency means that database users do not need to know on which node the required data resides.	incorrect	Fragmentation transparency refers to the fact that users can execute global queries, without being concerned with the fact that distributed fragments will be involved, and need to be combined, to perform the query.	incorrect	
MC	Many NoSQL databases apply some form of...	horizontal fragmentation.	correct	vertical fragmentation.	incorrect	
MC	Many NoSQL databases apply some form of...	horizontal fragmentation.	correct	vertical fragmentation.	incorrect	
MC	Eventual consistency in a NoSQL environment implies that...	the results of a database transaction will eventually be propagated to all replicas and if no further transactions are executed then the system will eventually become consistent.	correct	the database is inconsistent at all times.	incorrect	the results of a database transaction will immediately be propagated to all replicas.	incorrect	the database is consistent at all times.	incorrect	
MC	Which statement is NOT CORRECT?	With distributed 2PL, every site has its own lock manager, which is responsible for managing all locking data pertaining to the fragments stored on that site. 	incorrect	Primary site 2PL comes down to applying the centralized Two-Phase Locking protocol in a distributed environment. 	incorrect	A disadvantage of Primary site 2PL is that the central lock manager may become a bottleneck.	incorrect	Even if the database contains replicated data, applying the basic 2PL protocol still suffices to guarantee serializability. 	correct