不确定如何使用 Fluent NHibernate 从自定义查询中创建对象的属性

Question

我正在尝试映射以下结构：

public class Tag {
   public Guid Id {get;set;}
   public DateTime ActivatedDate {get;set;}
}

public class History {
   public Guid Id {get;set;}
   public TypeEnum Type {get;set;}
   public Guid ContentID {get;set;}
   public DateTime HistoryDate {get;set;}
}

Tag.ActivatedDate 实际上由 填充（从历史记录中选择前 1 个 HistoryDate，其中 ContentID = {tagid} && Type = 'Activated' order by HistoryDate desc

I我真的不知道如何使用 Fluent NHibernate 映射它

我的映射是：

public TagMapping() {
   Table("Tags");
   Id(x => x.Id)     
}

public HistoryMapping() {
   Table("History");
   Id(x => x.Id);
   Map(x => x.Type).CustomeType<TypeEnum>();
   Map(x => x.ContentID);
   Map(x => x.HistoryDate);
}

我不知道如何映射 Tag.ActivatedTop

基本上寻找：

SELECT tag.Id,
       (select top 1 HistoryDate from History 
               where ContentID = tag.Id 
                AND Status = 'Activated' 
        order by HistoryDate desc) As ActivatedDate
FROM Tags tag

Answer 1

最终做了：

  Map(x => x.ActivatedDate)
                .ReadOnly()
                .Formula(
                    string.Format(
                        "(select top 1 h.HistoryDate from History h where h.ContentID = Id AND h.Status = 'Activated' order by h.HistoryDate desc)"));