c# - NHibernate fluent (QueryOver) 用相关子查询替换 HQL

Question

背景，使用 FluentNHibernate，使用 NHibernate 3.0 的最新开发版本。

这是 WorkIncident 的类型声明:

// Enumeration used in class below.
public enum TicketStatus
{
    Open = 1,
    Closed = 10,
    Hold = 20
}

// Ticket class.
public class WorkIncident
{
    public virtual int EntryId { get; set; }
    public virtual int TicketNumber { get; set; }
    public virtual string ModifierNtId { get; set; }
    public virtual DateTime ModifiedDate { get; set; }
    public virtual TicketStatus Status { get; set; }
    public virtual int Version { get; set; }
    public virtual string Title { get; set; }
    public virtual string Details { get; set; }
}

// FluentNHibernate mapping
public class WorkIncidentMap : ClassMap<WorkIncident>
{
    public WorkIncidentMap()
    {
        Table("incident_details");
        Id( wi => wi.EntryId, "wiid");
        Map(wi => wi.TicketNumber, "workitem_number");
        Map(wi => wi.Title, "workitem_title");
        Map(wi => wi.Details, "workitem_comment");
        Map(wi => wi.ModifiedDate, "workitem_modified_on");
        Map(wi => wi.ModifierNtId, "modified_by_worker_nt_id");
        Map(wi => wi.Status, "workitem_status_lookup_id").CustomType<EnumType<Status>>();
        Map(wi => wi.Version, "workitem_version");
    }
}

映射工作正常，我可以毫无问题地进行如下查询:

session.QueryOver<AltirisIncident>()
    .Where(ai => ai.ModifierNtId == worker.Name.Replace("\\", @"\"))
    .AndRestrictionOn(ai => ai.ModifiedDate)
    .IsBetween(DateTime.Today)
    .And(DateTime.Today.AddDays(1))
    .List<WorkIncident>();

这为我提供了特定用户在当前日期触及的所有工作项(基本上是帮助台故障单)。

但是，我一直无法将以下 HQL 翻译成流畅的声明:

from    WorkIncident as t1
where   t1.ModifierNtId = :ntid
and     t1.ModifiedDate between :startdate and :enddate
and     t1.Status = :status
and     (t1.Version = 1
or      t1.TicketNumber in (
    select    t2.TicketNumber
    from      WorkIncident as t2
    where     t2.Status != t1.Status
    and       t2.TicketNumber = t1.TicketNumber
    and       t2.Version = t1.Version - 1))

此查询为我提供了由工作人员置于关闭状态的所有工作项的列表。考虑到工单在数据库中的存储方式(每张工单有多个记录(每次更新一个记录)并且主管通常会在工作人员关闭工单后向工单添加注释，导致我无法只查看工单的情况具有关闭状态的最后版本号，可以可靠地告诉我谁关闭了工单。

任何帮助将不胜感激，因为我更愿意尽可能地远离 HQL 和魔术字符串。

Answer 1

我认为这应该可以解决问题。困难的部分是真正处理你在那里的数学运算。你必须进入 SQLFunction 预测

session.QueryOver<WorkIncident>(() => t1Alias)
                .Where(w => w.ModifierNtId == "test")
                .And(w => w.ModifiedDate < DateTime.Now && w.ModifiedDate > DateTime.Now)
                .And(w => w.Status == TicketStatus.Open)
                .And(Restrictions.Disjunction()
                    .Add(Restrictions.Where<WorkIncident>(w => w.TicketNumber == 1))
                    .Add(Subqueries.WhereProperty(() => t1Alias.TicketNumber).In(
                        QueryOver.Of<WorkIncident>(() => t2Alias)
                                .Where(() => t2Alias.Status != t1Alias.Status)
                                .And(() => t2Alias.TicketNumber == t1Alias.TicketNumber)
                                .And(Restrictions.EqProperty(
                                    Projections.Property<WorkIncident>(w=> w.Version), 
                                    Projections.SqlFunction(
                                        new VarArgsSQLFunction("(","-",")"),
                                        NHibernateUtil.Int32,
                                        Projections.Property(()=> t1Alias.Version),
                                        Projections.Constant(1)
                                    )))
                                .Select(w => w.TicketNumber)))
                ).List();

在我的测试中，这生成了以下 SQL

 SELECT <snip...>
 FROM incident_details this_ 
 WHERE this_.modified_by_worker_nt_id = @p0 
    and (this_.workitem_modified_on < @p1 and this_.workitem_modified_on > @p2) 
    and this_.workitem_status_lookup_id = @p3 
    and (this_.workitem_number = @p4 
    or this_.workitem_number in 
        (SELECT this_0_.workitem_number as y0_ 
         FROM incident_details this_0_ 
         WHERE not (this_0_.workitem_status_lookup_id = this_.workitem_status_lookup_id) 
         and this_0_.workitem_number = this_.workitem_number 
         and this_0_.workitem_version = (this_.workitem_version-@p5)));
         @p0 = 'test' [Type: String (0)], @p1 = 10/26/2012 11:26:24 PM [Type: DateTime (0)], @p2 = 10/26/2012 11:26:24 PM [Type: DateTime (0)], @p3 = 1 [Type: Int32 (0)], @p4 = 1 [Type: Int32 (0)], @p5 = 1 [Type: Int32 (0)]