使用SetFetchMode

Question

打擾我的業餘nhibernate-ness，但我在下面的場景中抓取掙扎。

var query = session.CreateCriteria<Notification>().SetFetchMode("Parameters", FetchMode.Select) 
.CreateAlias("Parameters", "p", JoinType.InnerJoin) 
.Add(Restrictions.Where<Notification>(x => x.Acknowledged == false)); 

[一些建立一個IList代碼調用npHashes]

query = query.Add(Restrictions.In("p.PairHash", npHashes)).AddOrder(new Order("DateCreated", false)); 

[枚舉它]

請注意，我使用SELECT作爲prefetchmode ......，顯然就剩一個選項超出QueryOver ...和LINQ ...還要注意，獲取的表是與我已加入過濾的表相同的表。

執行該查詢的結果是：

SELECT 
    this_.Id as Id14_1_, 
    this_.Version as Version14_1_, 
    this_.Url as Url14_1_, 
    this_.DispatchType as Dispatch5_14_1_, 
    this_.Acknowledged as Acknowle6_14_1_, 
    this_.DateCreated as DateCrea7_14_1_, 
    this_.NotificationType as Notifica2_14_1_, 
    p1_.Id as Id15_0_, 
    p1_.Version as Version15_0_, 
    p1_.NotificationId as Notifica3_15_0_, 
    p1_.Name as Name15_0_, 
    p1_.Value as Value15_0_, 
    p1_.PairHash as PairHash15_0_ 
FROM 
    Notification this_ 
inner join 
    NotificationParameter p1_ 
     on this_.Id=p1_.NotificationId 
WHERE 
    this_.Acknowledged = ?p0 
    and p1_.PairHash in (
     ?p1 
    ) 
ORDER BY 
    this_.DateCreated desc; 
?p0 = False [Type: Boolean (0)], 
?p1 = 'V3zmXnv12B3AC26xeG10w+bas4U=' [Type: String (28)] 

所以第一個問題是，由於某種原因，NotificationParameter列包含在選擇列表...這似乎不是做一個選擇取回。這是不好的，因爲a）我想要一個選擇提取b）提取記錄被過濾。提取與加入（作爲一個概念）並不相同，並且加入的數據上的過濾器不應該（在這種情況下）過濾我提取的內容。

當然第二個問題是沒有發生SELECT提取。取而代之的是第一次訪問通知的Parameters屬性，它們被延遲加載：O

任何幫助？此外，如果使用QueryOver的方式來做到這一點，我寧願這樣做。我注意到，我可以去.UnderlyingCriteria.SetFetchmode（....），但是這對獲取的內容沒有影響。

Answer 1

在SQL你不能過濾和同時獲取所有。我還沒有熟悉查詢，但你應該明白。

var subquery = DetachedCriteria.For<Notification>() 
    .CreateAlias("Parameters", "p", JoinType.InnerJoin) 
    .Add(Restrictions.Where<Notification>(x => x.Acknowledged == false)) 
    .Add(Restrictions.In("p.PairHash", npHashes)) 
    .SetProjection(Projections.Id()); 

session.CreateCriteria<Notification>() 
    .Add(Subqueries.PropertyIn("Id", subquery)) 
    .SetFetchMode("Parameters", FetchMode.Eager) 
    .AddOrder(Order.Asc("DateCreated")) 
    .List<Notification>();