Question

A developer is designing a DynamoDB table for an IoT application that stores sensor readings. Each device sends multiple readings per day, and the most common access pattern is: 'Retrieve all readings for a specific device within a given time range.' The application must support this query efficiently without scanning the entire table. How should the developer design the table's primary key?

Accepted Answer

Use the device ID as the partition key and the reading timestamp as the sort key, then use a Query with a key condition on the timestamp range.

Answer

Use the reading timestamp as the partition key and the device ID as the sort key, then use a Query filtered by device ID.

Answer

Use a randomly generated UUID as the partition key for each reading and perform a Scan with a FilterExpression on device ID and timestamp.

Answer

Use the device ID as the partition key only, then use a Scan with a FilterExpression on the timestamp range.