DEA-C01 Data Ingestion and Transformation Practice Question
This DEA-C01 practice question tests your understanding of data ingestion and transformation. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company uses AWS DMS to migrate data from Oracle to Aurora MySQL. During the ongoing replication, the target table shows duplicate primary key errors. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Clue: "primary"
Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The target table has an auto-increment column, and DMS is inserting explicit values that conflict.
Duplicate PK errors often occur when the target table has an auto-increment column that conflicts with DMS inserts. Option A is correct. Option B is wrong because LOB mode doesn't cause duplicates. Option C is wrong because full LOB mode is for large objects. Option D is wrong because parallel threads can cause duplicates if not properly configured.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
DMS is using 'Limited LOB mode' and truncating LOB data, causing row mismatches.
Why it's wrong here
LOB truncation does not cause PK duplicates.
✗
The source table has a trigger that inserts additional rows.
Why it's wrong here
Triggers on source are not replicated by DMS.
✓
The target table has an auto-increment column, and DMS is inserting explicit values that conflict.
Why this is correct
DMS inserts values for the PK, but auto-increment may also generate values, causing duplicates.
Clue confirmation
The clue words "most likely", "primary" in the question point toward this answer.
Related concept
Standard ACLs match source addresses.
✗
The DMS task is configured with 'Parallel apply' threads that cause race conditions.
Why it's wrong here
Parallel apply should handle ordering; duplicates are more likely due to auto-increment.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.
TExam Day Tips
→Check inbound versus outbound direction.
→Read the ACL from top to bottom.
→Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related DEA-C01 ACL questions on filtering logic and placement.
Data Ingestion and Transformation — This question tests Data Ingestion and Transformation — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: The target table has an auto-increment column, and DMS is inserting explicit values that conflict. — Duplicate PK errors often occur when the target table has an auto-increment column that conflicts with DMS inserts. Option A is correct. Option B is wrong because LOB mode doesn't cause duplicates. Option C is wrong because full LOB mode is for large objects. Option D is wrong because parallel threads can cause duplicates if not properly configured.
What should I do if I get this DEA-C01 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related DEA-C01 ACL questions on filtering logic and placement.
Are there clue words in this question I should notice?
Yes — watch for: "most likely", "primary". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Standard ACLs match source addresses.
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Question Discussion
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