Amazon SimpleDB serves the purpose of cloud data storage in a structured architecture. It has greater reliability compared to the on-premise Oracle and MySQL data stores. While availability is way higher with this cloud relational data store, it is less complex when it comes to transaction management. Amazon SimpleDB is a better fit for applications that have the web content management requirement.

The features of Amazon SimpleDB include:

• A simple web-service-based data store
• Highly available clustered DBMS
• Highly scalable data storage system
• No need for maintaining an in-house DBA

Amazon SimpleDB is the best fit for NoSQL database access from cloud applications, not for applications with a requirement for powerful relational capabilities.