DynamoDB

Why DynamoDB table design starts from the queries your app runs, not from your entities - the mental shift from relational normalization to pattern-first modeling.

Design keys, sort-key range conditions, secondary indexes, updates, and batch writes in both boto3 and AWS SDK v3 - the working vocabulary beyond the first-table quickstart.

Read DynamoDB efficiently with Query, paginate via LastEvaluatedKey, understand why FilterExpression runs after the read, and when a Scan is acceptable - in boto3 and AWS SDK v3.

Capture every item change in DynamoDB with Streams - enable NEW_AND_OLD_IMAGES, trigger a Lambda on inserts/updates/deletes, or read the stream directly in boto3 and AWS SDK v3.

Test DynamoDB code without a live table - point boto3 and AWS SDK v3 at DynamoDB Local in Docker, mock with moto in Python, and structure fast, isolated tests.

A checklist for building on DynamoDB from the SDK - access-pattern-first key design, hot-partition avoidance, efficient reads, safe writes, TTL cleanup, capacity, and cost.