Which two items are key for maintaining data consistency in Oracle Database 12c?

Which two items are key for maintaining data consistency in Oracle Database 12c?

Which two items are key for maintaining data consistency in Oracle Database 12c?

A.
undo data

B.
isolation level

C.
lock mechanism

D.
serializability

Explanation:
http://docs.oracle.com/cd/E11882_01/server.112/e25789/consist.htm#CNCPT88969
(overview of the oracle database locking mechanism)



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Santosh

Santosh

other answer is B

Raja

Raja

B & C
Because undo-data and serialization are topics under LOCK MECHANISM & ISOLATION.

Sunil Vora

Sunil Vora

I’ll also gamble on B,C

Andre Rocha

Andre Rocha

https://docs.oracle.com/database/121/CNCPT/consist.htm#CNCPT221

A
Read Consistency and Undo Segments
To manage the multiversion read consistency model, the database must create a read-consistent set of data when a table is simultaneously queried and updated. Oracle Database achieves this goal through undo data.

D
To describe consistent transaction behavior when transactions run concurrently, database researchers have defined a transaction isolation model called serializability.

sudhakar

sudhakar

Answers should be A and C.

Undo will provide the pre-image if a data is being updated and locking mechanism provides the mechanism that will only allow a DML transaction per record at a time.

These will provide the consistency of the data.

raj

raj

it should be A & C

Yacoub Kanita

Yacoub Kanita

B and C