The correct answer is to use a Query with ScanIndexForward set to false and Limit 1. This works because DynamoDB stores items within a partition key in ascending order by the sort key; setting ScanIndexForward to false reverses that order, so the first item returned is the one with the highest sort key value—in this case, the latest timestamp. Adding Limit 1 ensures only that single most recent item is retrieved, making the operation both precise and efficient. On the AWS Certified Database Specialty DBS-C01 exam, this pattern tests your understanding of how DynamoDB’s sort key ordering and query parameters interact, and it often appears in scenarios involving time-series data or event logs. A common trap is confusing ScanIndexForward with a filter—it does not filter results but simply changes the traversal direction. Remember the memory tip: “False for the latest, true for the first” to recall that ScanIndexForward=false gives you the newest item per partition key.
DBS-C01 Management and Operations Practice Question
This DBS-C01 practice question tests your understanding of management and operations. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 has an Amazon DynamoDB table that stores IoT sensor data. The table has a partition key of device_id and a sort key of timestamp. The team wants to efficiently retrieve the latest reading for each device. Which query pattern should be used?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Query with ScanIndexForward=false and Limit=1
Option A is correct because using the Query API with ScanIndexForward set to false and Limit 1 will return the most recent item for a given partition key. Option B is wrong because ScanIndexForward=true returns items in ascending order, which would give the oldest item first. Option C is wrong because Scan operations scan the entire table and are inefficient. Option D is wrong because GetItem requires both partition and sort key; the sort key value is not known in advance.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Scan with FilterExpression to get the latest timestamp for each device
Why it's wrong here
Scanning is inefficient for large tables and does not guarantee the latest item per device without additional processing.
✗
Query with ScanIndexForward=true and Limit=1
Why it's wrong here
This returns the oldest item, not the latest.
✗
GetItem with the device_id and timestamp values
Why it's wrong here
GetItem requires the exact sort key value, which is not known when retrieving the latest reading.
✓
Query with ScanIndexForward=false and Limit=1
Why this is correct
This retrieves the most recent item for a given partition key by ordering the sort key in descending order and limiting to one result.
Related concept
Static NAT maps one inside address to one outside address.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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. NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated. 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.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DBS-C01 NAT questions on configuration and troubleshooting.
Management and Operations — This question tests Management and Operations — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Query with ScanIndexForward=false and Limit=1 — Option A is correct because using the Query API with ScanIndexForward set to false and Limit 1 will return the most recent item for a given partition key. Option B is wrong because ScanIndexForward=true returns items in ascending order, which would give the oldest item first. Option C is wrong because Scan operations scan the entire table and are inefficient. Option D is wrong because GetItem requires both partition and sort key; the sort key value is not known in advance.
What should I do if I get this DBS-C01 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DBS-C01 NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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Question Discussion
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