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

Chapter 4. The SimpleDB Data Model

The entire data model for SimpleDB is comprised of four concepts—domains, items, attributes, and values. We will explore these concepts in detail in this chapter. The conceptual hierarchy of a domain in SimpleDB is like the following chart and shows the relation between the different components.

In this chapter, we will cover:

  • Interacting with a domain

  • Metadata for a domain

  • Interacting with items in a domain

  • Interacting with the attributes of an item

  • Storing multiple values for an attribute

  • SimpleDB constraints on domain, items, attributes, and attribute values

  • Consistent Read and Conditional Put/Delete announced on February 24, 2010