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

Properties for Foreign Keys


Okay, so we know how to map all of the basic fields now, but what about those pesky Foreign Key fields, such as BillToContact_Id? How do we map those guys? They're mapped as int in the database, so we can just map them as int or Integer, right?

Technically, we could map them as int in our code, but that would make our work much more difficult when we go to use the actual object, and the reason we are using NHibernate is to make our job EASIER!

What we really need to do is map these fields as objects. As each of these fields links to another table (BillToContact_Id stores the ID from Contact) we can map these fields as objects and actually view these related objects.

For example, the OrderItem table has a parent-child relationship to the OrderHeader table using the field OrderHeader_Id, which links this table to the OrderHeader table. If I was looking at an order (OrderHeader), I would want to see all the items on that order (OrderItem). If I want to look at all the...