Book Image

Amazon SimpleDB Developer Guide

Book Image

Amazon SimpleDB Developer Guide

Overview of this book

SimpleDB is a highly scalable, simple-to-use, and inexpensive database in the cloud from Amazon Web Services. But in order to use SimpleDB, you really have to change your mindset. This isn't a traditional relational database; in fact it's not relational at all. For developers who have experience working with relational databases, this may lead to misconceptions as to how SimpleDB works.This practical book aims to address your preconceptions on how SimpleDB will work for you. You will be quickly led through the differences between relational databases and SimpleDB, and the implications of using SimpleDB. Throughout this book, there is an emphasis on demonstrating key concepts with practical examples for Java, PHP, and Python developers.You will be introduced to this massively scalable schema-less key-value data store: what it is, how it works, and why it is such a game-changer. You will then explore the basic functionality offered by SimpleDB including querying, code samples, and a lot more. This book will help you deploy services outside the Amazon cloud and access them from any web host.You will see how SimpleDB gives you the freedom to focus on application development. As you work through this book you will be able to optimize the performance of your applications using parallel operations, caching with memcache, asynchronous operations, and more.
Table of Contents (16 chapters)
Amazon SimpleDB Developer Guide
Credits
Foreword
About the Authors
About the Reviewers
Preface

Items


Items represent individual objects within each domain, and each item contains attributes with values. Each item is conceptually similar to a row in a spreadsheet. Items are distinguished by the presence of a unique ID, which can also be used when querying for a specific item.

Note

This unique identifier is not automatically provided by SimpleDB, and is the responsibility of the developer.

A common scheme followed by users of SimpleDB is to generate Globally Unique Identifiers or GUIDs and use them as the key for each item. You are not required to use this scheme and are free to generate this ID anyway you like as long as it is unique. The ID also needs to be unique only within the domain of interest.

Note

The February 24, 2010 announcement added capabilities that aid in doing a counter GUID. The Consistent Read and Conditional Put/Delete capabilities are documented at the end of this chapter.

You can add attributes to an item in SimpleDB. Any items that you create that do not have any attributes...