NHibernate的QueryOver與子查詢或其他想法如何可以工作？

Question

我有以下疑問：

Model.RampActiveHour rah = null; 

var defaultWeekQuery = QueryOver.Of<Model.RampAdditionalDefaultWeek>() 
            .Where(adw => adw.Ramp == rah.Ramp && 
              adw.Active && adw.FromDate <= date && 
              adw.ToDate >= date) 
            .Select(adw => adw.ID).Take(1); 
var result = session.QueryOver(() => rah) 
       .Where(ah => ah.DayOfWeek == date.DayOfWeek) 
       .WhereRestrictionOn(ah => ah.Ramp).IsIn((ICollection) ramps) 
       .WithSubquery.WhereProperty(ah=>ah.AdditionalDefaultWeek) 
        .Eq(defaultWeekQuery) 
       .List(); 

結果查詢：

SELECT 
this_.ID as ID3_0_, 
this_.DayOfWeek as DayOfWeek3_0_, 
this_.Active as Active3_0_, 
this_.SlotsCount as SlotsCount3_0_, 
this_.SlotId as SlotId3_0_, 
this_.SlotLength as SlotLength3_0_, 
this_.Date as Date3_0_, 
this_.ramp_id as ramp8_3_0_, 
this_.additional_default_week_id as additional9_3_0_, 
this_.Previous as Previous3_0_, 
this_.Next as Next3_0_ 
FROM RampActiveHour this_ 
WHERE this_.DayOfWeek = 3 /* ?p0 */ and 
this_.ramp_id in (
    3484 /* ?p1 */, 
    3498 /* ?p2 */) 
and 
    this_.additional_default_week_id = (
     SELECT 
      this_0_.ID as y0_ 
     FROM RampAdditionalDefaultWeek this_0_ 
     WHERE (
      (
       (
        this_0_.ramp_id = this_.ramp_id and 
         this_0_.Active = 1 /* ?p103 */) 
        and 
         this_0_.FromDate <= '2011-07-20T00:00:00.00' /* ?p104 */) 
        and 
         this_0_.ToDate >= '2011-07-20T00:00:00.00' /* ?p105 */) 
        limit 1 /* ?p106 */) 

查詢是正確的。問題在於，在我的模型中，我在RampActiveHour中有一個名爲AdditionalDefaultWeek的屬性，並且此屬性以多對一方式映射到RampAdditionalDefaultWeek表。這個多對一的關係可以爲null（這意味着沒有額外的默認周）或可以設置爲一個int（這意味着有活動的額外默認周）。

問題是，如果沒有活動的AdditionalDefaultWeek子查詢將返回空集，並且由於這個原因整個查詢返回空集。

我曾考慮Projections.Conditional預測，但仍然可以使這項工作。

任何幫助，非常感謝。

謝謝。

Answer 1

var result = session.QueryOver(() => rah) 
      .Where(ah => ah.DayOfWeek == date.DayOfWeek) 
      .WhereRestrictionOn(ah => ah.Ramp).IsIn((ICollection) ramps) 
      .WithSubquery.WhereProperty(ah=>ah.AdditionalDefaultWeek).Eq(defaultWeekQuery) 
      .Where(new Disjunction() 
       .Add(Subqueries.WhereProperty(ah=>ah.AdditionalDefaultWeek).Eq(defaultWeekQuery)) 
       .Add(new Conjunction() 
        .Add(Subqueries.WhereNotExists(defaultWeekQuery)) 
        .Add(Restrictions.Where(ah=>ah.AdditionalDefaultWeek == null))) 
      .List(); 

我不是查詢，以便在流利，所以有可能是一個更好的語法