Amazon Web Services yesterday announced its latest creation: SimpleDB. SimpleDB is a database-like storage service for structured data. It complements EC2 (the Elastic Compute Cloud) and S3 (the Simple Storage Service), potentially enabling web applications to run solely on Amazon's service stack. SimpleDB has a couple of limitations compared to traditional relational databases, the most important being:
- No joined queries against multiple tables (or domains, as Amazon puts it)
- No transactions protecting multiple updates
- No instant data updates, i.e. you might get "old" data when you query data that was updated very recently
We will have to wait and see what kind of applications SimpleDB can support regardless of these limitations. On the plus side we get the usual benefits of Amazon's Web Services:
- very good scalability
- high availability
- low cost / pay for usage
SimpleDB will enter a closed beta program very soon.
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