example_weblog.xml

<chapter id="example-weblog">
    <title>Example: Weblog Application</title>

    <sect1 id="example-weblog-classes">
        <title>Persistent Classes</title>

        <para>
            The persistent classes represent a weblog, and an item posted
            in a weblog. They are to be modelled as a standard parent/child
            relationship, but we will use an ordered bag, instead of a set.
        </para>

        <programlisting><![CDATA[using System;
using System.Collections.Generic;

namespace Eg
{
    public class Blog
    {
        public virtual long Id { get; set;}

        public virtual IList<BlogItem> Items { get; set;}

        public virtual string Name { get; set;}
    }
}]]></programlisting>

        <programlisting><![CDATA[using System;

namespace Eg
{
    public class BlogItem
    {
        public virtual Blog Blog { get; set;}

        public virtual DateTime DateTime { get; set;}

        public virtual long Id { get; set;}

        public virtual string Text { get; set;}

        public virtual string Title { get; set;}
    }
}]]></programlisting>

    </sect1>

    <sect1 id="example-weblog-mappings">
        <title>NHibernate Mappings</title>

        <para>
            The XML mappings should now be quite straightforward.
        </para>
        
        <programlisting><![CDATA[<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
    assembly="Eg" namespace="Eg">

    <class 
        name="Blog" 
        table="BLOGS" 
        lazy="true">
        
        <id 
            name="Id" 
            column="BLOG_ID">
            
            <generator class="native"/>
            
        </id>
        
        <property 
            name="Name" 
            column="NAME" 
            not-null="true" 
            unique="true"/>
            
        <bag
            name="Items" 
            inverse="true" 
            lazy="true"
            order-by="DATE_TIME" 
            cascade="all">
            
            <key column="BLOG_ID"/>
            <one-to-many class="BlogItem"/>
            
        </bag>
        
    </class>
    
</hibernate-mapping>]]></programlisting>

        <programlisting><![CDATA[<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
    assembly="Eg" namespace="Eg">
    
    <class 
        name="BlogItem" 
        table="BLOG_ITEMS" 
        dynamic-update="true">
        
        <id 
            name="Id" 
            column="BLOG_ITEM_ID">
            
            <generator class="native"/>
            
        </id>
        
        <property 
            name="Title" 
            column="TITLE" 
            not-null="true"/>
            
        <property 
            name="Text" 
            column="TEXT" 
            not-null="true"/>
            
        <property 
            name="DateTime" 
            column="DATE_TIME" 
            not-null="true"/>
            
        <many-to-one 
            name="Blog" 
            column="BLOG_ID" 
            not-null="true"/>
            
    </class>
    
</hibernate-mapping>]]></programlisting>

    </sect1>
    
    <sect1 id="example-weblog-code">
        <title>NHibernate Code</title>

        <para>
            The following class demonstrates some of the kinds of things
            we can do with these classes, using NHibernate.
        </para>

        <programlisting><![CDATA[using System;
using System.Collections.Generic;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Tool.hbm2ddl;

namespace Eg
{
    public class BlogMain
    {
        private ISessionFactory _sessions;

        public void Configure()
        {
            _sessions = new Configuration().Configure()
                .BuildSessionFactory();
        }

        public void ExportTables()
        {
            var cfg = new Configuration().Configure();
            new SchemaExport(cfg).Create(true, true);
        }

        public Blog CreateBlog(string name)
        {
            var blog = new Blog
            {
                Name = name,
                Items = new List<BlogItem>()
            };

            using (var session = _sessions.OpenSession())
            using (var tx = session.BeginTransaction())
            {
                session.Save(blog);
                tx.Commit();
            }

            return blog;
        }

        public BlogItem CreateBlogItem(Blog blog, string title, string text)
        {
            var item = new BlogItem
            {
                Title = title,
                Text = text,
                Blog = blog,
                DateTime = DateTime.Now
            };
            blog.Items.Add(item);

            using (var session = _sessions.OpenSession())
            using (var tx = session.BeginTransaction())
            {
                session.Update(blog);
                tx.Commit();
            }

            return item;
        }

        public BlogItem CreateBlogItem(long blogId, string title, string text)
        {
            var item = new BlogItem
            {
                Title = title,
                Text = text,
                DateTime = DateTime.Now
            };

            using (var session = _sessions.OpenSession())
            using (var tx = session.BeginTransaction())
            {
                var blog = session.Load<Blog>(blogId);
                item.Blog = blog;
                blog.Items.Add(item);
                tx.Commit();
            }

            return item;
        }

        public void UpdateBlogItem(BlogItem item, string text)
        {
            item.Text = text;

            using (var session = _sessions.OpenSession())
            using (var tx = session.BeginTransaction())
            {
                session.Update(item);
                tx.Commit();
            }
        }

        public void UpdateBlogItem(long itemId, string text)
        {
            using (var session = _sessions.OpenSession())
            using (var tx = session.BeginTransaction())
            {
                var item = session.Load<BlogItem>(itemId);
                item.Text = text;
                tx.Commit();
            }
        }

        public IList<object[]> ListAllBlogNamesAndItemCounts(int max)
        {
            IList<object[]> result;

            using (var session = _sessions.OpenSession())
            using (var tx = session.BeginTransaction())
            {
                var q = session.CreateQuery(
                    "select blog.id, blog.Name, count(blogItem) " +
                    "from Blog as blog " +
                    "left outer join blog.Items as blogItem " +
                    "group by blog.Name, blog.id " +
                    "order by max(blogItem.DateTime)"
                );
                q.SetMaxResults(max);
                result = q.List<object[]>();
                tx.Commit();
            }

            return result;
        }

        public Blog GetBlogAndAllItems(long blogId)
        {
            Blog blog = null;

            using (var session = _sessions.OpenSession())
            using (var tx = session.BeginTransaction())
            {
                var q = session.CreateQuery(
                    "from Blog as blog " +
                    "left outer join fetch blog.Items " +
                    "where blog.id = :blogId"
                );
                q.SetParameter("blogId", blogId);
                blog = q.UniqueResult<Blog>();
                tx.Commit();
            }

            return blog;
        }

        public IList<object[]> ListBlogsAndRecentItems()
        {
            IList<object[]> result = null;

            using (var session = _sessions.OpenSession())
            using (var tx = session.BeginTransaction())
            {
                var q = session.CreateQuery(
                    "from Blog as blog " +
                    "inner join blog.Items as blogItem " +
                    "where blogItem.DateTime > :minDate"
                );

                var date = DateTime.Now.AddMonths(-1);
                q.SetDateTime("minDate", date);

                result = q.List<object[]>();
                tx.Commit();
            }

            return result;
        }
    }
}]]></programlisting>

        <para>
            It requires some configuration settings in <literal>web.config</literal>, such as:
        </para>

        <programlisting><![CDATA[<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <!-- Add this element -->
  <configSections>
    <section
        name="hibernate-configuration"
        type="NHibernate.Cfg.ConfigurationSectionHandler, NHibernate" />
  </configSections>

  <!-- Add this element -->
  <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
    <session-factory>
      <property name="dialect">NHibernate.Dialect.MsSql2012Dialect</property>
      <property name="connection.connection_string">
        Server=localhost\SQLEXPRESS;initial catalog=Eg;Integrated Security=True
      </property>

      <mapping assembly="Eg" />
    </session-factory>
  </hibernate-configuration>

  <!-- Leave the other sections unchanged -->
  <system.web>
    ...
  </system.web>
</configuration>]]></programlisting>

    </sect1>

</chapter>