Hibernate for .NET - NHibernate Setup

Overview

Hibernate offers O/R mappings between Database and Java persistence classes. Many Java programmers get used to Hibernate would like to use the same technology (and syntax!) on their .NET projects too~ The answer to this is called NHibernate.
Below I will share my experience on how to set up NHibernate with C#, it should be similar for other .NET languages.

Reference

1. NHibernate Tutorial (1) - and ASP.NET
2. Installation And Running NHibernate
3. Your first NHibernate based application

Environment

• Database: SQL Server 2005
• NHibernate: 1.2.1 GA
• .NET Language: C#

Steps

Setup SQL Server Database

1. It is assumed that your Database is setup properly, so I will skip this step.

Download and install NHibernate

1. Download NHibernate at Here (I downloaded 1.2.1 GA-bin.zip)
2. Extract the zip file and navigate to folder "net-2.0"
3. We are going to use "NHibernate.dll" as reference in our project

Create Web Site and do NHibernate Configuration in VS

1. Add a Web Site to your Solution, and a C# class library project with name "Solution.Domain".
2. There are two ways to do configuration for NHibernate, one is by "System.Configuration.NameValueSectionHandler", the other is by "NHibernate.Cfg.ConfigurationSectionHandler". I choose to use method 2 because it is supported in NHibernate 2.0
3. Open "web.config" file and add "hibernate-configuration" section with the following code snippet:
   

   <configuration>

     <configSections>

           <section name="hibernate-configuration" type="NHibernate.Cfg.ConfigurationSectionHandler, NHibernate"/>

     </configSections>

     <!--

           NHibernate configuration

       -->

     <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">

       <session-factory>

         <property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property>

         <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>

         <property name="hibernate.connection.driver_class">NHibernate.Driver.SqlClientDriver</property>

         <property name="connection.connection_string">Server=(local);Initial Catalog=Test;Integrated Security=SSPI;</property>

         <mapping assembly="Solution.Domain" />

       </session-factory>

     </hibernate-configuration>

   </configuration>

4. Now we have the "web.config" ready, we still have to add two helper classes for handling NHibernate sessions. I extracted This zip file attached to Reference 1 and used the "NHibernateHttpModule.cs" and "SessionHelper.cs" files.
   However, I modified "SessionFactory" method in "SessionHelper.cs" as my configuration method is different from that of Reference 1.
   
   My modified "SessionFactory" method:
   

   private static ISessionFactory SessionFactory

           {

               get

               {

                   if (_sessionFactory == null)

                   {

                       Configuration config = new Configuration();

                       config.Configure();

                       _sessionFactory = config.BuildSessionFactory();

                       if (_sessionFactory == null)

                           throw new InvalidOperationException("Could not build SessionFactory");

                   }

                   return _sessionFactory;

               }

           }

Defines Mapping and the persistence class

1. The NHibernate mapping file is just like that of Hibernate: A XML file with extension ".hbm.xml". Here is my mapping file:
   

   <?xml version="1.0" encoding="utf-8" ?>

   <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="Solution.Domain" assembly="Solution.Domain">

    

     <class name="User" table="app_user">

       <id name="Username" column="username" type="String">

         <generator  class="assigned"/>

       </id>

       <property name="Name" column="name" type="String"/>

       <property name="Password" column="password" type="String"/>

     </class>

      

   </hibernate-mapping>

2. This XML mapping file must be included in the assembly with the name "Solution.Domain". To do this, right-click on the XML mapping file and select "properties", then choose "Embedded Resource" for "Build Action".
3. Next, let's move on to the persistence class.
   

   namespace Solution.Domain

   {

       public class User

       {

           public User()

           {

           }

    

           public virtual string Username

           {

               get;

               set;

           }

           public virtual string Name

           {

               get;

               set;

           }

           public virtual string Password

           {

               get;

               set;

           }

       }

   }

Show the result in ASP.NET page

1. Add a aspx page to the Web Site and then add the following code snippet to the aspx page:
   

   protected void Page_Load(object sender, EventArgs e)

       {

           ISession session = NHibernateHttpModule.CurrentSession;

           IQuery query = session.CreateQuery("FROM User");

           IList result = query.List();

    

           GridView1.DataSource = result;

           GridView1.DataBind();

       }

2. If everything works fine (and you have some Data in your SQL Server Table!), then you should see the data is retrieved and displayed on the aspx page~