NHibernate 3.2 mapping by code

NHibernate 3.2 will come with its own embedded mapping by code.

If you want know it is not based in fluent-interface, instead it is based on “loquacious”. That said you should understand that it has nothing related with Fluent-NHibernate.

The main idea under the NHibernate’s “sexy mapping” came from my dear ConfORM. In the past year the no conformist red man was running a lot and now I’m ready to transfer most of ConfORM’s intelligence directly inside NHibernate. To continue reading this post you have to run this song.

It’s simple (I’m too sexy)

Simple model

public class MyClass
{
    public int Id { get; set; }
    public string Something { get; set; }
}

Simple mapping

var mapper = new ModelMapper();
mapper.Class<MyClass>(ca =>
{
    ca.Id(x => x.Id, map =>
    {
        map.Column("MyClassId");
        map.Generator(Generators.HighLow, gmap => gmap.Params(new { max_low = 100 }));
    });
    ca.Property(x => x.Something, map => map.Length(150));
});

 

It’s flexible (I’m too sexy for my application)

You can organize your mapping as you want, class-by-class, different concerns about a class in different places and so on… (yes!! if you are a ConfORM user you know the concept)

var mapper = new ModelMapper();
mapper.Class<MyClass>(ca =>
{
    ca.Id(x => x.Id, map =>
    {
        map.Column("MyClassId");
    });
    ca.Id(x => x.Id, map =>
    {
        map.Generator(Generators.HighLow, gmap => gmap.Params(new { max_low = 100 }));
    });
    ca.Property(x => x.Something);
    ca.Property(x => x.Something, map => map.Length(150));
});

As you can see there is no problem duplicating the declaration of a mapped element and you can even do the same with the whole mapping of a class in two different places:

mapper.Class<MyClass>(ca =>
{
    ca.Id(x => x.Id, map =>
    {
        map.Generator(Generators.HighLow, gmap => gmap.Params(new { max_low = 100 }));
    });
    ca.Property(x => x.Something);
});

mapper.Class<MyClass>(ca =>
{
    ca.Id(x => x.Id, map =>
    {
        map.Column("MyClassId");
    });
    ca.Property(x => x.Something, map => map.Length(150));
});

 

It’s conventions friendly (too sexy by far)

You can apply “democratic” conventions

var mapper = new ModelMapper();

mapper.BeforeMapClass += 
    (mi, t, map) => map.Id(x => x.Column((t.Name+"id").ToUpper()));
mapper.BeforeMapProperty += 
    (mi, propertyPath, map) => map.Column(propertyPath.ToColumnName().ToUpper());

mapper.Class<MyClass>(ca =>
{
    ca.Id(x => x.Id, map => { });
    ca.Property(x => x.Something);
});

or you may want “republican” conventions

var mapper = new ModelMapper();

mapper.AfterMapClass +=
    (mi, t, map) => map.Id(x => x.Column((t.Name + "id").ToUpper()));
mapper.AfterMapProperty +=
    (mi, propertyPath, map) => map.Column(propertyPath.ToColumnName().ToUpper());

mapper.Class<MyClass>(ca =>
{
    ca.Id(x => x.Id, map => map.Column("Whatever"));
    ca.Property(x => x.Something, map => map.Column("Whatever"));
});

NHibernate 3.2 too sexy by far!!!