A dirty read occurs when a transaction reads data that has been modified by another transaction but not yet committed.Question 14AnswerTrueFalse

A phantom read problem may occur when a transaction changes the value of an object that has been read by another transaction several times.Question 4Select one:TrueFalse

What type of consistency level prevents all three phenomena: dirty read, non-repeatable read, and phantom read?Question 5Select one:A.Read CommittedB.Repeatable ReadC.Read UncommittedD.SerializableE.Snapshot Isolation

A lost update problem may occur between two transactions when these two transactions have read-write conflicts.Question 2Select one:TrueFalse

____ means that the data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.a)Consistencyb)Isolationc)Durabilityd)Atomicity

Which of the following scenarios may lead to an irrecoverable error in a database system?A transaction reads a data item after it is written by a committed transactionA transaction writes a data item after it is read by an uncommitted transactionA transaction reads a data item after it is written by an uncommitted transactionA transaction reads a data item after it is read by an uncommitted transaction