DynamoDB single-table design is a powerful pattern for modeling complex access patterns efficiently. This article walks through a real-world example showing how to design entity definitions, choose sort key patterns, and project only the attributes needed for each access pattern. We cover overlapping key prefixes, GSI overloading, and how to handle one-to-many and many-to-many relationships without secondary indexes. The article also discusses tradeoffs compared to normalized multi-table designs, when to choose which approach, and how to test your design before deploying to production. By the end you will have a clear framework for designing your own single-table schemas.