DEA-C01 Data Store Management Practice Question

Exhibit

Refer to the exhibit.

{
  "Tables": [
    {
      "TableName": "Orders",
      "KeySchema": [
        {"AttributeName": "order_id", "KeyType": "HASH"},
        {"AttributeName": "customer_id", "KeyType": "RANGE"}
      ],
      "AttributeDefinitions": [
        {"AttributeName": "order_id", "AttributeType": "S"},
        {"AttributeName": "customer_id", "AttributeType": "S"},
        {"AttributeName": "order_date", "AttributeType": "S"}
      ],
      "GlobalSecondaryIndexes": [
        {
          "IndexName": "CustomerDateIndex",
          "KeySchema": [
            {"AttributeName": "customer_id", "KeyType": "HASH"},
            {"AttributeName": "order_date", "KeyType": "RANGE"}
          ],
          "Projection": {"ProjectionType": "ALL"}
        }
      ]
    }
  ]
}

Refer to the exhibit. A DynamoDB table 'Orders' has a GSI 'CustomerDateIndex'. A developer tries to query the GSI for all orders of a customer between two dates. The query fails. What is the most likely reason?

⚠ Common exam trap

AWS often tests the misconception that any string date format works for range queries, but the trap here is that DynamoDB requires lexicographically sortable strings for BETWEEN conditions, and non-ISO formats will silently fail or return incorrect results.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

The query uses a date format that is not lexicographically sortable as a string

DynamoDB's Query operation requires the sort key to be lexicographically sortable when using comparison operators like BETWEEN. If the 'order_date' attribute is stored as a non-lexicographically sortable string format (e.g., 'MM-DD-YYYY' instead of 'YYYY-MM-DD'), the BETWEEN condition will fail to return correct results or may throw an error. The GSI's sort key must be in a format that supports string comparison for range queries to work properly.

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 GSI does not include 'order_id' in the key schema
Why it's wrong here
GSI keys are independent of table keys.
✗
The 'customer_id' attribute is not a partition key in the GSI
Why it's wrong here
It is defined as HASH key.
✓
The query uses a date format that is not lexicographically sortable as a string
Why this is correct
String sort on dates requires ISO 8601 format.
✗
The 'order_date' attribute is not a sort key in the GSI
Why it's wrong here
It is defined as RANGE key.

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DEA-C01 Data Store Management Practice Question

Exhibit

Why each option matters

Option-by-option breakdown

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