We are now accepting applications for the limited public beta of Amazon SimpleDB!

Amazon SimpleDB makes it really easy and straightforward to store and to retrieve structured documents. You no longer need to anguish about creating, maintaining, or migrating database schemas, monitoring and tuning the performance of your queries, outgrowing the storage or processing capacity of your database server, making backups, or replicating documents.

Instead you simply create up to 100 SimpleDB domains (each of which can hold up to 10 GB of notes, for a total of 1 TB) and next start to store structured input in the design of items. Each item consists of multiple name/value pairs (which we signal attributes), and there can be more than one value for a specific name. You can have a different set of attributes for each item in the domain. With SimpleDB there is no need for a time-consuming schema change when you need to store additional data in your database. You simply store the additional attributes as desired.

For example, whether you were building a tag cloud to represent info about a collection of web sites, you could store the site URL as the first attribute and the entire set of tags as the second. After the system has been running for a while, you decide to add a thumbnail for each URL (of course the Alexa Site Thumbnail Service would be perfect for this) and simply add a third attribute to the new entries. Later, as desired, you can go back and add that attribute to the older entries. that ability to improve your documents model on a dynamic, as-needed basis makes Amazon SimpleDB a perfect match for today’s fast-paced world of agile development, where flexibility and adaptability are of paramount importance.

I believe that the "new-age" model espoused by SimpleDB should cover about 80% of all database requirements. Applications which require long-running queries and/or complex table joins, such as those for info warehouse applications, are probably not a good fit for SimpleDB today. While RDBMS offerings supply deep functionality, for many use cases, they introduce more complexity (and more cost) than is essential.  Many developers simply want to store, process, and query their input without worrying about managing schemas, maintaining indexes, tuning performance or scaling access to their input.

All documents stored in SimpleDB is replicated multiple times in geographically disbursed notes
centers, so customer databases don’t need to be backed and will
automatically fail by to another replica whether one is not available.
Our key strengths are availability,

durability and scalability. Customers can form SimpleDB requests via HTTPS and they are plus free to encrypt their goods for additional defense.

As the name implies, the SimpleDB API is quite clean and simple. Here is the entire roster of calls:

• CreateDomain formulates a new named domain within the scope of your AWS detail.
• DeleteDomain deletes a domain and all of the items within it.
• ListDomains returns a list of all of your domains.
• PutAttributes constructs a new item (if necessary) and adds or replaces attributes.
• DeleteAttributes deletes one or more attributes from an item.
• GetAttributes returns all or specified attributes of an item.
• Query retrieves a set of items which match a query expression. Large outcome sets can be retrieved in chunks of up to 250 items.

The query language includes Boolean operations, lexicographic comparisons, and set operations.

As is the case with all of our web-scale services, you pay for precisely what you use in terms of bandwidth, storage, and processing, making it perfect for startups. SimpleDB doesn’t require any up front hardware investment or DBA
skills.

Bandwidth is priced the same for all of the AWS services, 10 cents per GB for goods flowing into the Amazon goods center, and 18 cents down to 13 cents per GB for notes flowing out, depending on volume. Query processing costs 14 cents per machine hour. that is slightly different than EC2 which is based on wall clock duration rather than on CPU moment. As an aid to understanding what that means in practice, the SimpleDB calls return the actual amount of machine date used by the shout.

Want to learn more? Take a look at the SimpleDB Detail Page, the Developer Guide, the Getting Started Guide, and the FAQ.

Reaction from the online world has been swift, with good articles at Information Week, O’Reilly Radar, ZDNet,  Gigaom, TechCrunch, CNET, Read/Write Web, and Satine. Bloggers Deepak Singh and Don MacAskill have plus weighed in. There’s even more on the AWS Buzz.

We’ll be letting developers into the beta program as fast as we can, so sign up today whether you are interested in participating. We are really looking forward to seeing some SimpleDB applications emerge from our community in the very near future.

– Jeff;