Fluent-nhibernate with .net core NHibernate.Driver.MySqlDataDriver

Question

What did I do wrong here? I've installed the nhibernate, fluentnhibernate and System.Data.SqlClient nuget packages. I am new to nhibernate and ORM on general.

Here code and error:

public class Animal
{
    public virtual int Id { get; set; }
    public virtual string Name { get; set; }
}


public class AnimalMap : ClassMap<Animal>
{
    public AnimalMap() {
        Id(x => x.Id);
        Map(x => x.Name);
        Table("animals");
    }
}

Demo.js

public class Demo
{
    private static ISessionFactory _sessionFactor;
    private static ISessionFactory SessionFactory{
        get {
            if(_sessionFactor == null) {
                InitializeSessionFactory();
            }
            return _sessionFactor;
        }
    }

    private static void InitializeSessionFactory () {
        DbProviderFactories.RegisterFactory("System.Data.SqlClient", SqlClientFactory.Instance);
        _sessionFactor = Fluently.Configure()
        .Database(MySQLConfiguration.Standard
        .ConnectionString(
            "Server=localhost;Database=xxx;Uid=root;Pwd=666;"
        ))
        .Mappings(mappings => mappings.FluentMappings
        .AddFromAssemblyOf<Program>())
        .ExposeConfiguration(cfg => new SchemaExport(cfg)
        .Create(true, true))
        .BuildSessionFactory();
    }

    public static ISession OpenSession() {
        return SessionFactory.OpenSession();
    }
}

Program.cs

static void Main(string[] args)
    {
        using (var session = Demo.OpenSession()) {
            using (var transaction = session.BeginTransaction()) {
                var animal = new Animal {
                    Name = "Cat"
                };
                session.Save(animal);
                transaction.Commit();
            }
        }
    }

When I run this .net core console application, I get the error below

Unhandled exception. FluentNHibernate.Cfg.FluentConfigurationException: An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection, and InnerException for more detail.

---> FluentNHibernate.Cfg.FluentConfigurationException: An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection, and InnerException for more detail.

---> NHibernate.HibernateException: Could not create the driver from NHibernate.Driver.MySqlDataDriver, NHibernate, Version=4.0.0.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4. ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.ArgumentException: The specified invariant name 'MySql.Data.MySqlClient' wasn't found in the list of registered .NET Data Providers. at System.Data.Common.DbProviderFactories.GetFactory(String providerInvariantName, Boolean throwOnError) at System.Data.Common.DbProviderFactories.GetFactory(String providerInvariantName) at NHibernate.Driver.ReflectionBasedDriver..ctor(String providerInvariantName, String driverAssemblyName, String connectionTypeName, String commandTypeName) at NHibernate.Driver.MySqlDataDriver..ctor()
--- End of inner exception stack trace --- at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean wrapExceptions, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& hasNoDefaultCtor) at System.RuntimeType.CreateInstanceDefaultCtorSlow(Boolean publicOnly, Boolean wrapExceptions, Boolean fillCache) at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, Boolean wrapExceptions) at System.Activator.CreateInstance(Type type, Boolean nonPublic, Boolean wrapExceptions) at System.Activator.CreateInstance(Type type) at NHibernate.Bytecode.ActivatorObjectsFactory.CreateInstance(Type type) at NHibernate.Connection.ConnectionProvider.ConfigureDriver(IDictionary`2 settings)
--- End of inner exception stack trace --- at NHibernate.Connection.ConnectionProvider.ConfigureDriver(IDictionary'2 settings) at NHibernate.Connection.ConnectionProvider.Configure(IDictionary'2 settings) at NHibernate.Connection.ConnectionProviderFactory.NewConnectionProvider(IDictionary'2 settings) at NHibernate.Tool.hbm2ddl.SchemaExport.Execute(Action'1 scriptAction, Boolean execute, Boolean justDrop, TextWriter exportOutput) at NHibernate.Tool.hbm2ddl.SchemaExport.Execute(Action'1 scriptAction, Boolean execute, Boolean justDrop) at NHibernate.Tool.hbm2ddl.SchemaExport.Execute(Boolean useStdOut, Boolean execute, Boolean justDrop) at NHibernate.Tool.hbm2ddl.SchemaExport.Create(Boolean useStdOut, Boolean execute) at nhibernatetutorial.Demo.<>c.b__3_1(Configuration cfg) in C:\Users\user\nhibernatetutorial\Demo.cs:line 31 at FluentNHibernate.Cfg.FluentConfiguration.BuildConfiguration() --- End of inner exception stack trace --- at FluentNHibernate.Cfg.FluentConfiguration.BuildConfiguration() at FluentNHibernate.Cfg.FluentConfiguration.BuildSessionFactory()

--- End of inner exception stack trace --- at FluentNHibernate.Cfg.FluentConfiguration.BuildSessionFactory() at nhibernatetutorial.Demo.InitializeSessionFactory() in C:\Users\user\nhibernatetutorial\Demo.cs:line 24 at nhibernatetutorial.Demo.get_SessionFactory() in C:\Users\user\nhibernatetutorial\Demo.cs:line 16 at nhibernatetutorial.Demo.OpenSession() in C:\Users\user\nhibernatetutorial\Demo.cs:line 37 at nhibernatetutorial.Program.Main(String[] args) in C:\Users\user\nhibernatetutorial\Program.cs:line 9

Giulio Caccin Giulio Caccin · Accepted Answer · 2019-11-03T08:27:58

By looking into your exception:

'MySql.Data.MySqlClient' wasn't found in the list of registered .NET Data Providers

You can see that nhibernate cannot instantiate the driver for mysql because of a missing dependency.
You need to add a provider in the configurations like this:

<entityFramework>
  <providers>
    <provider invariantName="MySql.Data.MySqlClient"
              type="MySql.Data.MySqlClient.MySqlProviderServices, MySql.Data.Entity.EF6" />
  </providers>
</entityFramework>

For additional info you can take a look at the official mysql connector documentation.

Fluent-nhibernate with .net core NHibernate.Driver.MySqlDataDriver

1 Answers