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

The FieldNames structure


One of the most useful things we can do (especially if we are using some sort of code generation to keep it in sync!) is to generate a FieldNames structure. One of the complaints that I hear from other developers coming to NHibernate is that the queries aren't strongly typed, so if the database structure changes or if they have a typo in their code, they won't know at compile time that they have broken code.

Traditional NHibernate queries are generally written as follows:

criteria.Add(Restriction.Eq("FirstName", fName);

In this case, if we change the field name in the database from FirstName to FName (and we don't adjust our mapping file, and leave FName to map to FirstName in our class), our code will compile just fine. However, when we run it, we will get a runtime exception because the FirstName field doesn't exist on our object.

One simple way to overcome this issue is to use a FieldNames structure, which simply maps string names of the properties to a local structure...