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 5. Data Types

SimpleDB stores the values for all attributes in your items as UTF-8 strings. This means that all comparisons between attributes to determine order or to match search criteria will be done lexicographically. Your application needs to be aware of this fact and encode data correctly before saving it to SimpleDB and decode the data correctly on retrieval from SimpleDB. Coding of dates and numbers is necessary in SimpleDB if the application will search for a value or sort on the values. All values in SimpleDB are treated as case-sensitive and must be taken into consideration. SimpleDB leaves the data type conversions to the developer, and thus provides you with a lot of flexibility in dealing with your data that is to be stored in SimpleDB. In this chapter, we will look at different kinds of data types and the encoding and decoding strategies to be used when storing and retrieving them from SimpleDB.

In this chapter, we will cover:

  • Lexicographical comparison

  • Storing numbers...