Disadvantages of the SimpleDB model
SimpleDB's alternative approach also has some disadvantages compared to a relational database for certain applications.
Those using applications that always need to ensure immediate consistency of data will find that SimpleDB's eventual data consistency model may not suit their needs. The consistent read announcement does change this, but the eventual consistency model is still the basis of the extreme scalability.
Using SimpleDB as the data storage engine in your applications needs the development team to get used to different concepts over a simple, traditional RDBMS.
Because relationships are not explicitly defined at the schema level as in a relational database, you might need to enforce some data constraints within your application code.
If your application needs to store data other than strings, such as numbers and dates, additional effort will be required on your part to encode the strings before storing them in the SimpleDB format.
The ability to have...
