1Z0-064 · Question #90
Which two statements are true regarding undo data records?
The correct answer is A. They are required to support Flashback features. E. Undo records contain copies of data as it appears before a change is made. Exam Questions, Study Guides, Practice Tests. Lead the way to help you pass any IT Certification exams, 100% Pass Guaranteed or Full Refund. Especially Cisco, CompTIA, Citrix, EMC, HP, Oracle, VMware, Juniper, Check Point, LPI, Nortel, EXIN and so on. Our Slogan: First Test…
Question
Which two statements are true regarding undo data records?
Options
- AThey are required to support Flashback features.
- BThey are not required if Flashback features are enabled.
- CThey are retained until the session making the changes ends.
- DUndo records contain copies of data as it appears after a change is made.
- EUndo records contain copies of data as it appears before a change is made.
How the community answered
(33 responses)- A73% (24)
- B3% (1)
- C9% (3)
- D15% (5)
Explanation
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Topics
Community Discussion
8
Fatima Z.Dec 23, 2025The answers are A and E, and here is your sticky hook: think "UNDO = UNDo Over" meaning undo records store the BEFORE image (not after), like a time-machine snapshot of what the data looked like pre-change, and Oracle's Flashback features literally need that before-picture to rewind time, so no undo means no flashback, period.
Prof. SaraJan 6, 2026The correct answers are A and E. Undo records hold the before-image of data, meaning the values as they existed prior to the change, which is what Oracle uses both to roll back uncommitted transactions and to serve consistent reads, and that same before-image data is exactly what powers Flashback features like Flashback Query and Flashback Table. A quick memory hook: think "UNDO equals BEFORE," and remember that Flashback is just Oracle reaching back into that same undo stream, so if you disable or expire undo too soon you kill both read consistency and your Flashback window at the same time.
Hiroshi T.Jan 14, 2026I initially circled C thinking undo records stuck around for the session, but the Oracle Database Concepts guide is clear that retention is governed by the undo retention parameter and tablespace availability, not session lifecycle. Once I went back to the definition, E locked in immediately since undo stores the before-image of changed data, and A follows directly from the Flashback chapter which explicitly states that Flashback queries and Flashback Table rely on undo data to reconstruct prior row versions.
Nina C.Dec 4, 2025D tripped me up, but undo is before-images, so A and E.
Ola B.Dec 6, 2025Solid instinct on the before-images, though worth spinning up a test transaction in a SQL sandbox to watch the undo segment actually capture those original values, because seeing it live tends to make the concept stick in a way that just reading about it never does.
Lena V.Jan 2, 2026Saw this exact wording on mine, picked A and E without blinking, moved on.
Ola B.Dec 19, 2025A is solid, E is the one you need to burn into memory because D is sitting right there trying to trip you up, undo blocks store the BEFORE image so Oracle can roll things back or let another session read a consistent snapshot. Spin up a test instance, fire off an update without committing, then query v$undostat and v$transaction to watch it in action, that before-image concept will click fast once you see the segment filling up.
Orla P.Dec 29, 2025A and E are solid picks here. Undo records store the before-image of data, which is exactly what Oracle needs to roll back transactions and power Flashback features like Flashback Query, so both functions depend on the same undo mechanism.