Amazon SimpleDB vs Amazon RDS

Question

I work at a small ecommerce site and we're looking to move to all Amazon hosted services and I'm unsure the exact difference in RDS and SimpleDB. RDS can use MySQL, can SimpleDB not?

Answer 1

Simply put, I would assume that because your business model is e-commerce that you need transactional consistency in your data solution. Because of this, you should choose one of the RDS options (these are MySQL, Oracle or SQL Server).

AWS SimpleDB is a non-relational data store (or NoSQL), so what you get is flexibility (i.e. schema-less or schema-light) and scalability, but what you don't get is immediate (transactional) consistency and also the query pattern will not use joins.

Answer 2

RDS is basically a relational database in the SQL vein, whereas SDB is a non-relational database. I'd recommend reading through all the info on the Amazon Web Services (AWS) site, as they answer all the questions you might have.

From the AWS FAQs:

Q: When would I use Amazon RDS vs. Amazon EC2 Relational Database AMIs vs. Amazon SimpleDB?
Amazon Web Services provides a number of database alternatives for developers. Amazon RDS enables you to run a fully featured relational database while offloading database administration; Amazon SimpleDB provides simple index and query capabilities with seamless scalability; and using one of our many relational database AMIs on Amazon EC2 and Amazon EBS allows you to operate your own relational database in the cloud. There are important differences between these alternatives that may make one more appropriate for your use case.

More information about AWS database options