NHibernate QueryOver 与子查询或其他想法如何工作？

Question

我有以下疑问:

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();

结果查询是:

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 */)

查询是正确的。问题是在我的模型中，我在 RampActiveHour 中有一个名为 AdditionalDefaultWeek 的属性，并且该属性以多对一的方式映射到 RampAdditionalDefaultWeek 表。这种多对一关系可以为空(这意味着没有额外的默认周)或可以设置为 int(这意味着有事件的额外默认周)。

问题是，如果没有事件的 AdditionalDefaultWeek，子查询返回空集，因此整个查询返回空集。

我想到了 Projections.Conditional 投影，但仍然可以完成这项工作。

任何帮助深表感谢。

谢谢。

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();

我不太擅长查询，所以可能有更好的语法