Recently I installed the current version of the N2CMS to power my personal homepage. I’m running on shared webhosting so you may imagine how poor performance is. To speed up the thing a little I decided to switch from SqlCe database to the full blown SQL Server.

However, after changing the connection string the N2CMS does not even install itself:

Attempt by method 'NHibernate.AdoNet.SqlClientSqlCommandSet..ctor()' to access method 'System.Data.SqlClient.SqlCommandSet..ctor()' failed.

If you carefully look at the source code of the NHibernate.AdoNet.SqlClientSqlCommandSet, you will discover the ugly reflection:

    /// 

    /// Expose the batch functionality in ADO.Net 2.0
    /// Microsoft in its wisdom decided to make my life hard and mark it internal.
    /// Through the use of Reflection and some delegates magic, I opened up the functionality.
    ///     
    /// Observable performance benefits are 50%+ when used, so it is really worth it.
    /// 
    
    public class SqlClientSqlCommandSet 
...

        static SqlClientSqlCommandSet()
        {
            Assembly sysData = Assembly.Load("System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089");
            sqlCmdSetType = sysData.GetType("System.Data.SqlClient.SqlCommandSet");
            Debug.Assert(sqlCmdSetType != null, "Could not find SqlCommandSet!");
        }

To continue installing, either make the reflection work by switching your application to full trust (provided your hosting company will allow this):

or disable NHibernate batching feature (and you will lose “observable performance benefirst 50%+” as the author of the NHibernate comment claims ) by following the commit message:

Enabling batching is done by defining (the new) property "hibernate.batch_size" to a size greater than zero. This way require an explicit action to enable it, but this is probably a good thing.

Today just a small snippet of code. If you unlucky one inherited some brownfield database with awkward lowercase_and_underscores naming convention (I really hate it):

and you are using NHibernate with Fluent automapping configuration, just use this property convention:

private class ColumnConvention : IPropertyConvention
{
    public void Apply(FluentNHibernate.Conventions.Instances.IPropertyInstance instance)
    {
        var regexString = @"([A-Z][\w^[A-Z]]*)([A-Z][\w^[A-Z]]*)*";

        var newName = Regex.Replace(instance.Name, regexString, (m => (m.Index != 0 ? "_" : "") + m.Value.ToLower()));

        instance.Column(newName);
    }
}

Of course, the real gem here is the regex itself (days without writing regexes are awesome).

If you forgot how to apply a custom convention, here you go:

SessionFactory =
    Fluently.Configure().Database(
        MsSqlConfiguration.MsSql2008.ConnectionString(c => c.FromConnectionStringWithKey("SugarCrmDb"))).
        Mappings(
            m => m.AutoMappings.Add(AutoMap.
                                        AssemblyOf(cfg).
                                        Override(am => am.Table("accounts")).
                                        Conventions.Add(new ColumnConvention())
                        )
        ).
        BuildSessionFactory();