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

Attributes


Each item will have attributes, which are similar in concept to a column in a spreadsheet or a column in a database table. Each attribute is a key/value pair. The key is the unique name for the attribute and the value is the textual data for that key. SimpleDB is schemaless and allows you to have different attributes for each item in a domain. This is impossible in a relational database world where you must define your table schemas up front, and every time you need to add a new field or column, you must upgrade the schema for the database, or your existing applications might start throwing errors. SimpleDB frees you from this upgrade and maintenance cycle, and gives you the freedom to use this flexibility to your advantage when designing your applications.

If you add a new attribute to an item in a domain, only that item will have that attribute, and all the other existing items in the domain will hum along nicely without that additional attribute! You can see this in the following...