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

Coding some GetX() methods


We want to have GetById() and GetAll() methods at least, as these methods are used frequently.

The simplest get method that we will code is the GetById() method, which is not just cleverly named, but should also retrieve an object by its ID. This method is really simple to code, because NHibernate already knows how to go get an object using its unique identifier.

To retrieve a record by its ID, all we have to do is call Session.Get<T>() and pass it an ID.

Note

If you haven't seen the <T> syntax before (or the (Of T) syntax in VB.NET), it is the .NET syntax for generics. It simply means ANY TYPE, so <T> for our Contact object would be <Contact> or (Of Contact).

An example of the GetById() method would look as follows:

public Contact GetById(int Id)
{
  return Session.Get<Contact>(Id);
}

The VB.NET code looks very similar, we just substitute the (Of T) syntax for the <T> syntax of C#:

Public Function GetById(ByVal Id As Integer) As Contact...