R – What’s the most productive way to do NHibernate mapping

fluent-nhibernatemappingnhibernatenhibernate-mapping

I know annotations to do the hibernate mapping in Java and am looking now for a similar way to do the same in C# and NHibernate. I found out that there exists several approaches

do the mapping in xml files
NHibernate.Mapping.Attributes (NHMA)
Fluent
are there any more??

I tried NHMA and found out it had some blocking points for me…

I don't want you to discuss, whats the best way to map models to NHibernate, but I was looking for a good comparison on the internet.

Do you know such sites? What facts are the main points to consider, if I choose one of the "frameworks" listed above? I'm thinking of aspects like 'is this project offically supported by the NH-Developers?', 'are there models that can be mapped in xml-mapping but not in fluent/NHMA/etc…?'

What can you recommend?
Why?

Best Answer

Fluent NHibnernate auto mapping or code generation (CodeSmith, MyGeneration, T4, etc.) are the most productive ways to create the mapping files. I dislike the attributes approach because I like to keep my POCOs plain.

Related Solutions

C# – NHibernate mapping after a normalisation

As I've asked in the comments; how does this FundBalance class exactly looks like ? What goes in there ? Can you do something with the <join table> element in the NHibernate mapping ?

For example: http://ayende.com/Blog/archive/2007/04/24/Multi-Table-Entities-in-NHibernate.aspx

Inheritance Mapping with Fluent NHibernate

I know this is really old, but it is now pretty simple to set up fluent to generate the exact mapping you initially desired. Since I came across this post when searching for the answer, I thought I'd post it.

You just create your ClassMap for the base class without any reference to your subclasses:

public class ItemMap : ClassMap<Item>
{
    public ItemMap()
    {
        this.Table("Item");
        this.DiscriminateSubClassesOnColumn("ItemType");
        this.Id(x => x.ItemId, "ItemId");
        this.Map(x => x.FieldA, "FieldA");
    }
}

Then map your abstract subclass like this:

public class SubItemMap: SubclassMap<SubItemMap>
{
    public SubItemMap()
    {
        this.Map(x => x.FieldB);
    }
}

Then map your concrete subclasses like so:

public class ConcreteItemXMap : SubclassMap<ConcreteItemX>
{
    public ConcretItemXMap()
    {
        this.Join("ConcreteItemX", x =>
        {
            x.KeyColumn("ItemID");
            x.Map("FieldC")
        });
    }
}

Hopefully this helps somebody else looking for this type of mapping with fluent.

Best Answer

Related Solutions

C# – NHibernate mapping after a normalisation

Inheritance Mapping with Fluent NHibernate

Related Topic