The correct answer is that the Lambda function can write items but cannot read items from the DynamoDB table. This outcome occurs because AWS IAM uses explicit deny logic, where a Deny statement for `dynamodb:GetItem` overrides any Allow statements, even if an Allow for `dynamodb:PutItem` is present. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of how IAM policy evaluation works with DynamoDB, specifically the principle that an explicit Deny always trumps an Allow, regardless of order. A common trap is assuming that an Allow for write operations implies read access, but the explicit Deny on read is absolute. To remember this, think of the IAM evaluation logic as a strict hierarchy: explicit Deny is the final word, like a "veto" that cannot be overruled by any Allow.
DBS-C01 Workload-Specific Database Design Practice Question
This DBS-C01 practice question tests your understanding of workload-specific database design. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Refer to the exhibit. An IAM policy is attached to an IAM role used by a Lambda function that writes to a DynamoDB table. The function also needs to read items from the table. What is the outcome of this policy?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The Lambda function can write items but cannot read items
The IAM policy includes an explicit Deny for the `dynamodb:GetItem` action on the table, which overrides any Allow statements due to the explicit deny evaluation logic in AWS IAM. Since the Lambda function assumes a role with this policy, it is denied read access while the Allow for `dynamodb:PutItem` permits write operations. Therefore, the function can write but cannot read items from the DynamoDB table.
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.
✗
The policy is invalid because it contains both Allow and Deny for the same table
Why it's wrong here
The policy is valid; Deny takes precedence.
✗
The Lambda function can both read and write items
Why it's wrong here
The Deny statement explicitly denies reads.
✓
The Lambda function can write items but cannot read items
Why this is correct
The Deny for GetItem overrides the Allow, so reads fail.
Related concept
Read the scenario before looking for a memorised answer.
✗
The Lambda function cannot perform any operations on the table
Why it's wrong here
PutItem is allowed.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume a single Allow statement grants all actions on a resource, overlooking that an explicit Deny for a specific action will block that action even if other actions are allowed.
Detailed technical explanation
How to think about this question
AWS IAM policy evaluation logic follows an explicit deny override: if any policy (identity-based or resource-based) includes an explicit Deny for an action, that action is denied regardless of any Allow statements. In this case, the Deny on `dynamodb:GetItem` blocks reads, while the Allow on `dynamodb:PutItem` remains effective. This is commonly used to enforce least privilege by explicitly blocking sensitive operations while permitting others.
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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
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.
Workload-Specific Database Design — This question tests Workload-Specific Database Design — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The Lambda function can write items but cannot read items — The IAM policy includes an explicit Deny for the `dynamodb:GetItem` action on the table, which overrides any Allow statements due to the explicit deny evaluation logic in AWS IAM. Since the Lambda function assumes a role with this policy, it is denied read access while the Allow for `dynamodb:PutItem` permits write operations. Therefore, the function can write but cannot read items from the DynamoDB table.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This DBS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DBS-C01 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.