Book Image

NHibernate 2 Beginner's Guide

By : Aaron Cure
Book Image

NHibernate 2 Beginner's Guide

By: Aaron Cure

Overview of this book

<p>NHibernate is an open source object-relational mapper, or simply put, a way to retrieve data from your database into standard .NET objects. Quite often we spend hours designing the database, only to go back and re-design a mechanism to access that data and then optimize that mechanism. This book will save you time on your project, providing all the information along with concrete examples about the use and optimization of NHibernate.<br /><br />This book is an approachable, detailed introduction to the NHibernate object-relational mapper and how to integrate it with your .NET projects. If you're tired of writing stored procedures or maintaining inline SQL, this is the book for you.<br /><br />Connecting to a database to retrieve data is a major part of nearly every project, from websites to desktop applications to distributed applications. Using the techniques presented in this book, you can access data in your own database with little or no code.<br /><br />This book covers the use of NHibernate from a first glance at retrieving data and developing access layers to more advanced topics such as optimization and Security and Membership providers. It will show you how to connect to multiple databases and speed up your web applications using strong caching tools. We also discuss the use of third-party tools for code generation and other tricks to make your development smoother, quicker, and more effective.</p>
Table of Contents (19 chapters)
NHibernate 2
Credits
About the Author
About the Reviewers
Preface
Index

Relationships


One of the goals of our database design is to reduce the duplication of data and logically group different types of data into different tables. A logical separation would be for things like contacts. If we wanted to store all of our contacts, their phone numbers, addresses, and so on, then we could store it in a table, as shown in the following screenshot:

At first glance, this looks like a pretty elegant solution that would work fine. What if I want to store a contact without an address? Can I do this? Currently the table doesn't allow NULL values in the address fields, so I would have to change that. How about storing more than one address like a work and a home address? What about multiple phone numbers? The list goes on. What we really need here is a way to logically store grouped data in its own table, and relate it to other pieces of data. This is called a relationship, and it is probably the single most powerful concept in database design ever. By allowing a relational...