How to use NHibernate with both MySQL server and Microsoft SQL server 2008

Question

How can I configure NHibernate to connect to both a MySQLserver and a Microsoft SQL server 2008? I do want to copy data from one server to another. I heard of NHibernate shared.

Answer 1

I've struggled quite a bit few months ago. My problem was with MS Sql Server and Oracle.

What I've done is to create two separate config files for nhibernate:

sql.nhibernate.config

    
      
      
        NHibernate.Connection.DriverConnectionProvider
        NHibernate.Driver.SqlClientDriver
        NHibernate.Dialect.MsSql2008Dialect
        
        web
        100
        120
        3
        true
        true 1, false 0, yes 'Y', no 'N'
        NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle
        
      

ora.nhibernate.config

  
  
    NHibernate.Connection.DriverConnectionProvider
    NHibernate.Driver.OracleDataClientDriver
    NHibernate.Dialect.Oracle10gDialect
    
    web
    100
    120
    3
    true
    true 1, false 0, yes 'Y', no 'N'
    NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle
    
  

I use this simple class to build my nhibernate SessionFactory:

    public class NHibernateSessionFactory
    {
        private ISessionFactory sessionFactory;

        private readonly string ConnectionString = "";
        private readonly string nHibernateConfigFile = "";

        public NHibernateSessionFactory(String connectionString, string nHConfigFile)
        {
            this.ConnectionString = connectionString;
            this.nHibernateConfigFile = nHConfigFile;
        }

        public ISessionFactory SessionFactory
        {
            get { return sessionFactory ?? (sessionFactory = CreateSessionFactory()); }
        }

        private ISessionFactory CreateSessionFactory()
        {
            Configuration cfg;
            cfg = new Configuration().Configure(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, this.nHibernateConfigFile));

            // With this row below Nhibernate searches for the connection string inside the App.Config.
            // cfg.SetProperty(NHibernate.Cfg.Environment.ConnectionStringName, System.Environment.MachineName);
            cfg.SetProperty(NHibernate.Cfg.Environment.ConnectionString, this.ConnectionString);

#if DEBUG
            cfg.SetProperty(NHibernate.Cfg.Environment.GenerateStatistics, "true");
            cfg.SetProperty(NHibernate.Cfg.Environment.ShowSql, "true");
#endif

            return (cfg.BuildSessionFactory());
        }
    }

As you can see I pass to my NHibernateSessionFactory a connection string (I prefer to save it in my app config file) and the name (without the path) of the nhibernate config file.

I personally use a DI container (StructureMap) and you can achieve something very cool defining a registry class:

public class NhibernateRegistry : Registry
{
    public NhibernateRegistry()
    {

        For()
        .Singleton()
        .Add(new NHibernateSessionFactory(, "ora.nhibernate.config").SessionFactory)
        .Named("OracleSF");

        For()
        .HybridHttpOrThreadLocalScoped()
        .Add(o => o.GetInstance("OracleSF").OpenSession())
        .Named("OracleSession");

        For()
        .Singleton()
        .Add(new NHibernateSessionFactory(, "sql.nhibernate.config").SessionFactory)
        .Named("MsSqlSF");

        For()
        .HybridHttpOrThreadLocalScoped()
        .Add(o => o.GetInstance("MsSqlSF").OpenSession())
        .Named("MsSqlSession");
    }
}

in which you can use named instances. My services layer than uses a StructureMap registry class where you can define the constructors:

this.For()
     .HybridHttpOrThreadLocalScoped()
     .Use()
     .Ctor("sessionMDII").Is(x => x.TheInstanceNamed("OracleSession"))
     .Ctor("sessionSpedizioni").Is(x => x.TheInstanceNamed("MsSqlSession"));

For your Service implementation:

public class OrdersService : IOrdersService
{
        private readonly ISession SessionMDII;
        private readonly ISession SessionSpedizioni;

        public OrdersService(ISession sessionMDII, ISession sessionSpedizioni)
        {
            this.SessionMDII = sessionMDII;
            this.SessionSpedizioni = sessionSpedizioni;
        }

    ...
}