Multiple Databases

The built-in dependency-injection helper, AddNHibernateWithSingleDatabase, registers exactly one ISessionFactory/ISession/IStatelessSession/ITransactionManager set per application — as the name says, it targets the single-database case, and there is currently no first-class, out-of-the-box registration helper for multiple databases in one process.

The codebase still carries an ISessionFactoryKeyProvider interface from an earlier multi-database design, but nothing in SharpArch.NHibernate implements or consumes it today — treat it as a leftover extension point, not a supported feature.

If you need more than one database

You can still wire up multiple NHibernate session factories yourself, on top of NHibernateSessionFactoryBuilder, using ASP.NET Core’s keyed services (available since .NET 8):

services.AddKeyedSingleton("Northwind", (sp, _) =>
    new NHibernateSessionFactoryBuilder()
        .AddMappingAssemblies(new[] { typeof(Northwind.Infrastructure.AssemblyMarker).Assembly })
        .UseConfigFile("NorthwindNHibernate.config")
        .BuildSessionFactory());

services.AddKeyedSingleton("Village", (sp, _) =>
    new NHibernateSessionFactoryBuilder()
        .AddMappingAssemblies(new[] { typeof(Village.Infrastructure.AssemblyMarker).Assembly })
        .UseConfigFile("VillageNHibernate.config")
        .BuildSessionFactory());

Then resolve ISessionFactory per database with [FromKeyedServices("Northwind")], open your own ISession/IStatelessSession scoped per request from each keyed factory, and register a repository implementation per database (a repository class per (entity, database) pair, since NHibernateRepository takes a single ISession in its constructor).

This is considerably more manual than the single-database path — budget for writing your own scoped-session and transaction-manager wiring for the second (and subsequent) databases.