The answer is to disable foreign key constraints on the target Aurora PostgreSQL database before migration and re-enable them after the full load completes. This is the most efficient approach because AWS DMS performs parallel table loads without respecting dependency order; with constraints active, child rows can be inserted before their parent rows, triggering foreign key violations and causing migration failures. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of DMS migration strategies under the “Migration” domain, specifically how to handle referential integrity during heterogeneous migrations. A common trap is attempting to load tables in a specific dependency sequence, which is impractical with hundreds of tables and often leads to timeouts. Instead, disabling constraints sidesteps the ordering problem entirely. Memory tip: think “disable, load, enable” — like turning off a gate to let all traffic through, then locking it afterward to ensure order.
DBS-C01 Deployment and Migration Practice Question
This DBS-C01 practice question tests your understanding of deployment and migration. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 is migrating a self-managed Oracle database to Amazon Aurora PostgreSQL using AWS DMS. The source database has a large number of tables with foreign key constraints. During the full load phase, some tables fail to load due to foreign key violations. What is the most efficient way to resolve this?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Disable foreign key constraints on the target before migration and re-enable after
Option C is correct because disabling foreign key constraints on the target Aurora PostgreSQL database before the migration allows DMS to load tables in any order without violating referential integrity. After the full load completes, re-enabling the constraints ensures data consistency. This approach is the most efficient as it avoids complex dependency ordering and reduces migration failures.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Increase the DMS task memory and parallel load threads
Why it's wrong here
This improves performance but does not resolve constraint violations.
✗
Use the table preparation mode 'Do nothing' and load tables in dependency order
Why it's wrong here
Manually ordering tables is error-prone and may still cause violations.
✓
Disable foreign key constraints on the target before migration and re-enable after
Why this is correct
This allows flexible loading order and avoids violations.
Related concept
Read the scenario before looking for a memorised answer.
✗
Pre-create all target tables with the same constraints and use 'Truncate' mode
Why it's wrong here
Pre-creating with constraints still causes violations if load order is wrong.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think increasing resources (Option A) or pre-creating tables (Option D) will solve the issue, but they overlook that foreign key violations are a logical dependency problem, not a performance or schema creation issue.
Detailed technical explanation
How to think about this question
Under the hood, AWS DMS performs parallel table loads by default, which can lead to child tables being loaded before parent tables, causing foreign key violations. Disabling constraints (e.g., using `SET session_replication_role = 'replica'` in PostgreSQL) temporarily bypasses referential integrity checks, allowing DMS to load data without errors. After migration, re-enabling constraints (e.g., `ALTER TABLE ... VALIDATE CONSTRAINT`) ensures all foreign key relationships are verified, maintaining data integrity.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Deployment and Migration — This question tests Deployment and Migration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Disable foreign key constraints on the target before migration and re-enable after — Option C is correct because disabling foreign key constraints on the target Aurora PostgreSQL database before the migration allows DMS to load tables in any order without violating referential integrity. After the full load completes, re-enabling the constraints ensures data consistency. This approach is the most efficient as it avoids complex dependency ordering and reduces migration failures.
What should I do if I get this DBS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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