16A shared (S) lock allows:AOthers to writeBOnly the DBA to readCOther transactions to read but not write the itemDNo access at allView AnswerDiscussWorkspaceReportSaveEasy
17A 'lost update' happens when:AThe log is lostBData is deleted by mistakeCTwo transactions overwrite each other's changesDA transaction reads uncommitted dataView AnswerDiscussWorkspaceReportSaveEasy
18Two-phase locking (2PL) guarantees:ANo locking at allBNo deadlocksCConflict-serializable schedulesDFaster commitsView AnswerDiscussWorkspaceReportSaveMedium
19Which property ensures committed changes survive a crash?AAtomicityBConsistencyCDurabilityDIsolationView AnswerDiscussWorkspaceReportSaveEasy
20What does ACID stand for?AAtomicity, Concurrency, Integrity, DurabilityBAtomicity, Consistency, Isolation, DurabilityCAccuracy, Concurrency, Integrity, DataDAccess, Control, Isolation, DataView AnswerDiscussWorkspaceReportSaveEasy