复杂的NHibernate的QueryOver表达 [英] Complex nHibernate QueryOver expression

问题描述

我有一个层次 A>的下列对象; B> C> ð。每个对象被映射到表中。我想写使用QueryOver的SQL语句：

I have the following objects in a hierarchy A > B > C > D. Each object is mapped to a table. I'm trying to write the following SQL using QueryOver:

SELECT B
FROM A, B, C, D
WHERE A.ID = B.ID
  AND B.ID = C.ID
  AND C.ID = D.ID
WHERE A.NUMBER = 'VALUE'
  AND D.NAME IN ('VALUE1', 'VALUE2')

我的C＃代码到目前为止：

I have the C# code so far:

string[] entityNames = entityAttributes.Select(e => e.Name).ToArray();
string customerNumber = 2;

return session.QueryOver<B>()
              .JoinQueryOver(b => b.C)
              .JoinQueryOver(c => c.D)
              .WhereRestrictionOn(d => d.Name).IsIn(entityNames)
              .List<B>();

现在缺少的这里是 A>乙链接。我无法弄清楚如何添加加盟 A 限制它放在 NUMBER 字段。我尝试以下，但 .JoinQueryOver（B => BC）正在寻求键入 A ，而不是寻找类型 b

What's missing here is the A > B link. I cannot figure out how to add the join to A restricting it on the NUMBER field. I tried the following but the .JoinQueryOver(b => b.C) is looking for type A instead of finding type B.

return session.QueryOver<B>()
                .JoinQueryOver(b => b.A)
                    .Where(a => a.Number == customerNumber)
              .JoinQueryOver(b => b.C) **//Looks for type A instead of B**
              .JoinQueryOver(c => c.D)
              .WhereRestrictionOn(d => d.Name).IsIn(entityNames)
              .List<B>();

我如何添加类型 A 此查询，同时还返回类型 b ？

How can I add type A to this query while still returning type B?

推荐答案

您可以使用别名来加入你的表像

you can use Aliases to join your table like

B tB = null;
A tA = null;
C tC = null;
D tD = null;
var qOver = HibSession.QueryOver<B>(() => tB)
.JoinAlias(() => tB.A, () => tA, JoinType.LeftOuterJoin)
.Where(() => tA.Number == customerNumber)
.JoinAlias(() => tB.C, () => tC, JoinType.LeftOuterJoin)
.JoinAlias(() => tC.D, () => tD, JoinType.LeftOuterJoin)
.Where(Restrictions.On(() => tD.Name).IsIn(entityNames))
.List<B>();

我希望这是有帮助的。

I hope it's helpful.

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