What does the term "degree 3 consistency" ensure in a transaction?Question 24Select one:A.Transaction T does not read dirty data from other transactions.B.Other transactions do not dirty any data read by T before T completes.C.Transaction T does not overwrite dirty data of other transactions.D.Transaction T does not commit any writes until it completes all its writes.E.All the choices apply

____ 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

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

For the consistency property of database transactions, it requires that the state of a database is consistent before and after each transaction, but the intermediate states of a database during a transaction do not need to be consistent.Question 3Select one:TrueFalse

Atomicity. A transaction is an atomic unit of processing; it should either beperformed in its entirety or not performed at all.■ Consistency preservation. A transaction should be consistency preserving,meaning that if it is completely executed from beginning to end withoutinterference from other transactions, it should take the database from oneconsistent state to another.■ Isolation. A transaction should appear as though it is being executed in iso-lation from other transactions, even though many transactions are executing7Undo and redo are discussed more fully in Chapter 23.21.4 Characterizing Schedules Based on Recoverability 755concurrently. That is, the execution of a transaction should not be interferedwith by any other transactions executing concurrently.■ Durability or permanency. The changes applied to the database by a com-mitted transaction must persist in the database. These changes must not belost because of any failure.

What is the purpose of “degree-two consistency”? Select one: a. To avoid cascading aborts without necessarily ensuring serializability. b. To avoid serializable aborts without necessarily ensuring a cascade. c. To avoid aborting cascades without serializing ensurability. d. To abort cascading avoidances without ensuring serializability. e. To ensure cascading aborts without avoiding serializability