While SimpleDB has scaling limitations,it may be a good fit for
smaller workloads that require query flexibility. Amazon SimpleDB
automatically indexes all item attributes and thus supports query
flexibility at the cost of performance and scale.

因此，它是性能/可扩展性和简单性/灵活性之间的折衷，即对于更简单的场景，使用SimpleDB可能更容易开始，以避免为您的DynamoDB应用程序构建复杂性(见下面的不同透视图)。

链接的常见问题条目还引用了Werner Vogel的Amazon DynamoDB – a Fast and Scalable NoSQL Database Service Designed for Internet Scale Applications，这确实是一个详尽的，因此强烈推荐阅读亚马逊的Nosql的历史，特别是Dynamo;它包含更多的洞察解决您的问题，例如。

It became obvIoUs that developers [even Amazon engineers] strongly preferred simplicity to
fine-grained control as they voted “with their feet” and adopted
cloud-based AWS solutions,like Amazon S3 and Amazon SimpleDB,over
Dynamo. [addition mine]

显然DynamoDB已经被介绍来解决这个问题，因此可以被认为是SimpleDB的继承者，而不是“只是”修改他们现有的Nosql产品：

We concluded that an ideal solution would combine the best parts of
the original Dynamo design (incremental scalability,predictable high
performance) with the best parts of SimpleDB (ease of administration
of a cloud service,consistency,and a table-based data model that is
richer than a pure key-value store).

Werner的摘要建议DynamoDB适合任何大小的应用程序现在相应地：

Amazon DynamoDB is designed to maintain predictably high performance and to be highly cost efficient for workloads of any scale,from the smallest to the largest internet-scale applications.