Question

嗨，我是NHibernate的新手，无法在聚合的自我组合中加入。我认为展示我想要实现的SQL可能有所帮助：

数据看起来像这样：

Message TABLE
ID  DIRECTION   BATCHID SEQUENCE    ISLASTINSEQUENCE        
1   Outbound    1       1           0   
2   Outbound    1       2           0       
3   Outbound    1       3           1

查询如下所示：

--Get all msgs with batchId where full sequence is ready
SELECT      *
FROM        [Message] M
JOIN        (
            --Group Msg on batchId and Count Sequence + cross ref using having
            SELECT      M.BatchId
            FROM        [Message] M
            JOIN        (
                        --Get BatchId of last msg in sequence
                        SELECT      BatchId,  Sequence as LastInSequence
                        FROM        [Message]
                        WHERE       Direction = 'Outbound' 
                        AND         IsEndOfSequence  = 1
                        ) M1 ON M.BatchId = M1.BatchId
            WHERE       Direction = 'Outbound'
            GROUP BY    M.BatchId, LastInSequence
            HAVING      count(1) = M1.LastInSequence
            ) B ON M.BatchId = B.BatchId

基本上我想要包含我有完整序列的批次

这可能是HNibernate Linq的尝试：

var lastInSeqenceMsgs =
    from b in Query<Message>(x => x.Direction == MessageDirection.Outbound 
                             && x.IsEndOfSequence)
    select new {b.BatchId, LastInSequence = b.Sequence};

var fullSequenceBatchIds = 
    from outboundMessage in Query<Message>(x => x.Direction == 
                                           MessageDirection.Outbound)
    join lastInSequence in (lastInSeqenceMsgs)
        on outboundMessage.BatchId equals lastInSequence.BatchId
    group lastInSequence by new {lastInSequence.BatchId, lastInSequence.LastInSequence}
    into g
    where g.Count() == g.Key.LastInSequence
    select g.Key.BatchId;

var allMsgsFromWithCompleteSequences =
    from fullSequenceMessage in Query<Message>(x => x.Direction ==
                                               MessageDirection.Outbound)
    join test in (fullSequenceBatchIds) on
        fullSequenceMessage.BatchId equals test.BatchId
    select test;

它对第二个查询进行了轰炸（我评估了查询 - 未显示），但有以下异常：

无法转换类型为＃System; Linq.Expressions.NewExpression＆＃39;的对象输入＆＃39; Remotion.Linq.Clauses.Expressions.QuerySourceReferenceExpression＆＃39;。

其中我提炼回到自我加入

var fullSequenceBatchIds =
        from outboundMessage in Query<Message>(x => x.Direction ==
                                                   MessageDirection.Outbound)
        join lastInSequence in (lastInSeqenceMsgs)
            on outboundMessage.BatchId equals lastInSequence.BatchId
        select outboundMessage;

我得到了例外＆＃34;不支持指定的方法。＆＃34;

我的额头上有砖印，所以非常感谢这里的一些帮助。

Answer 1

一般来说，我只能说nhibernate Linq提供商不支持Linq提供的所有内容。

此外，nhibernate不支持子查询。它根本不起作用，你必须以某种方式解决它。

NHibernate加入了自我的聚合计数

1 个答案: