Snippet for 2010 blog post "NHibernate and Mapping Aggregates"

NHAggregates.cs

public class IdeaMap : ClassMap<Idea>
{
    public IdeaMap()
    {
        Id(x => x.Id)
            .Column("ID")
            .GeneratedBy.Identity();

        Map(x => x.Summary).Not.Nullable();
        Map(x => x.Description).WithMaxSize().Not.Nullable();
        Map(x => x.Created).Not.Nullable();
        Map(x => x.LastStatusChange).Not.Nullable();
        Map(x => x.Visible).Not.Nullable();
        Map(x => x.Status).Not.Nullable();

        Map(x => x.CommentCount)
            .Formula("(select count(*) from Comment c where c.IdeaId = ID)");

        HasMany(x => x.Votes).KeyColumn("IdeaId")
            .Inverse().Cascade.AllDeleteOrphan();

        HasMany(x => x.Comments).KeyColumn("IdeaId")
            .Cascade.All();

        References(x => x.Category).Column("CategoryId")
            .Not.Nullable();

        References(x => x.CreatedBy).Column("UserId")
            .Not.Nullable();

        Cache.ReadWrite();
    }
}