NHibernate - Configuration


In this chapter, we will look at NHibernate configuration. We have different ways that we can configure NHibernate. It divides into two main groups

  • XML-based configuration
  • Code-based configuration

Code-Based Configuration

The code-based configuration is built into NHibernate. It was introduced around the NHibernate 3 and we have used the code bases configuration up till now.

String Data Source = asia13797\\sqlexpress;
String Initial Catalog = NHibernateDemoDB;
String Integrated Security = True;
String Connect Timeout = 15;
String Encrypt = False;
String TrustServerCertificate = False;
String ApplicationIntent = ReadWrite;
String MultiSubnetFailover = False;

cfg.DataBaseIntegration(x = > { x.ConnectionString = "Data Source + 
   Initial Catalog + Integrated Security + Connect Timeout + Encrypt +
   TrustServerCertificate + ApplicationIntent + MultiSubnetFailover"; 
   x.LogSqlInConsole = true; 


All the configurations are specified in the C# code. You can see here that we have got our new configuration object, and then we use loquacious configuration that was introduced with NHibernate 3.1 to configure the database. What connection string we are using, what database we are connecting to and the dialect to use. We also add our mapping assembly directly to here.

XML-Based Configuration

If you are using XML-based configuration, you can use a hibernate.cfg.xml file, which is just a standalone xml file using the NHibernate schema, or you can embed that NHibernate specific configuration inside of your app or web.cfg. The hibernate.cfg.xml name is by default, but we can use an arbitrary name for that xml file as well.

Let’s have a look into the XML-based configuration by adding a new xml file to the NHibernateDemoApp project and call it hibernate.cfg.xml.

Enter the following information into the hibernate.cfg.xml file.

<?xml version = "1.0" encoding = "utf-8" ?> 
<hibernate-configuration xmlns = "urn:nhibernate-configuration-2.2"> 
      <property name = "connection.connection_string">
         Data Source = asia13797\\sqlexpress;
         Initial Catalog = NHibernateDemoDB;
         Integrated Security = True;
         Connect Timeout = 15;
         Encrypt = False;
         TrustServerCertificate = False;
         ApplicationIntent = ReadWrite;
         MultiSubnetFailover = False;
      <property name = "connection.driver_class">
      <property name = "dialect">
      <mapping assembly = "NHibernateDemoApp"/>

As you can see in the above xml file, we have specified the same configuration as mentioned in the C#.

Now let’s comment on this configuration from the Program.cs file and just call the Configure() method, which will load the hibernate.cfg.xml file as shown below.

using HibernatingRhinos.Profiler.Appender.NHibernate; 
using NHibernate.Cfg; 
using NHibernate.Dialect; 
using NHibernate.Driver; 

using System; 
using System.Linq; 
using System.Reflection; 

namespace NHibernateDemoApp { 

   class Program { 
      static void Main(string[] args) { 
         var cfg = new Configuration(); 
         //cfg.DataBaseIntegration(x =>
            // x.ConnectionString = "Data Source = asia13797;\\sqlexpress
            Initial Catalog = NHibernateDemoDB;
            Integrated Security = True;
            Connect Timeout = 15;
            Encrypt =False;
            TrustServerCertificate = False;
            ApplicationIntent = ReadWrite;
            MultiSubnetFailover = False"; 
            // x.Driver<SqlClientDriver>(); 
            // x.Dialect<MsSql2008Dialect>(); 
            // x.LogSqlInConsole = true; 
         var sefact = cfg.BuildSessionFactory();
         using (var session = sefact.OpenSession()) { 
            using (var tx = session.BeginTransaction()) { 
               var students = session.CreateCriteria<Student>().List<Student>(); 
               Console.WriteLine("\nFetch the complete list again\n"); 
               foreach (var student in students) { 
                  Console.WriteLine("{0} \t{1} \t{2} \t{3}", student.ID,
                     student.FirstName, student.LastName, student.AcademicStanding); 

Let’s run your application again and you will see the same output.

Fetch the complete list again

1 Allan Bommer Excellent
2 Jerry Lewis Good