NHibernate 对合并日期的比较约束

Question

这里有一个很好的问答来解决这个问题： NHibernate COALESCE issue

我需要能够将日期对象与内部联接中的日期值进行比较。这里不熟悉的领域是这个 COALESCE 的实现以及日期 LT 约束

这是我当前的 SQL 查询

SELECT DISTINCT Sites.*
FROM Sites
 INNER JOIN Sites_WF_Info
       ON Site_Key = SiteWFInfo_Site_Key
       AND SiteWFInfo_Effective_Date <= @today
       AND @today <= SiteWFInfo_End_Date
 INNER JOIN Profit_Centers
       ON Site_Key = ProfCtr_Site_Key
       AND ProfCtr_Open_Date <= @today
       AND @today < Coalesce(ProfCtr_Close_Date, '6/6/2079')

我想知道的是如何使用常量代替 ExpenseReport.PeriodFrom 属性 ==> left。

理想情况下，我想设置左/右

// DateTime effDate is passed in
var left = Projections.Property<DateTime>(effDate);
var right = Projects.SqlFunction("COALESCE",
            NHibernateUtil.DateTime,
            Projections.Constant(DateTime.Parse("6/6/2079").Date, NHibernateUtil.DateTime),
            Projections.Property<ProfitCenter>(pc => pc.CloseDate));

然后，当调用限制时

var restriction = Restrictions.LtProperty(left, right);

这样当我构建 QueryOver 时，我可以用这个 restriction 对象替换 Where 子句之一

var foo = CurrentSession().QueryOver<Site>(() => sa)
    .Inner.JoinQueryOver<ProfitCenter>(() => pca)
    .Where(restriction)

---

最终答案

这需要引入一个新的“扁平化”域“ResultModel”(SiteWithWindowsTimezoneId)，以便我可以从查询中返回更具体的模型，并避免延迟加载当前与 Site 关联的所有其他内容。这种新的查询样式已将 16+ sql 查询方法变为单个查询。节省的时间是值得的。再次感谢您的帮助。我希望这个要点对将来的某人有所帮助。

SiteWorkforceInfo swia = null;
SiteWorkforceConfig swcfg = null;
ProfitCenter pca = null;
Site sa = null;
SiteWithWindowsTimezoneId siteResult = null;

var leftProfCloseDate = Projections.Constant(effectiveDate);
var rightProfCloseDate = Projections.SqlFunction("COALESCE", 
    NHibernateUtil.DateTime, 
    Projections.Property<ProfitCenter>(pc => pc.CloseDate),
    Projections.Constant(DateTime.Parse("6/6/2079").Date, NHibernateUtil.DateTime)
);

var profCloseDateRestriction = Restrictions.LtProperty(leftProfCloseDate, rightProfCloseDate);

var activeSites = CurrentSession().QueryOver<SiteWorkforceInfo>(() => swia)
    .Inner.JoinQueryOver<Site>(() => swia.Site, () => sa)
    .Left.JoinQueryOver<SiteWorkforceConfig>(() => sa.SiteWFConfig, () => swcfg)
    .Inner.JoinQueryOver<ProfitCenter>(() => sa.ProfitCenters, () => pca)
    .Where(() => swia.EffectiveDate <= effectiveDate)
    .Where(() => effectiveDate <= swia.EndDate)
    .Where(() => pca.OpenDate <= effectiveDate)
    .Where(profCloseDateRestriction)
    .Where(() => swia.TimeCaptureRule > 0)
    .SelectList(
        list => list
            .Select(() => sa.Key).WithAlias(() => siteResult.Key)
            .Select(() => sa.Id).WithAlias(() => siteResult.Id)
            .Select(() => sa.IdFormatted).WithAlias(() => siteResult.IdFormatted)
            .Select(() => sa.Description).WithAlias(() => siteResult.Description)
            .Select(() => swcfg.WindowsTimezoneId).WithAlias(() => siteResult.WindowsTimezoneId)
                )
    .TransformUsing(Transformers.AliasToBean<SiteWithWindowsTimezoneId>())
    .List<SiteWithWindowsTimezoneId>();

return activeSites;

--- 结果查询 ---

SELECT sa1_.Site_Key as y0_, 
    sa1_.Site_Id as y1_, 
    sa1_.Site_Id_Formatted as y2_, 
    sa1_.Site_Description as y3_, 
    swcfg2_.SiteWFCfg_Windows_Timezone_Id as y4_ 
FROM Sites_WF_Info this_ 
inner join Sites sa1_ 
    on this_.SiteWFInfo_Site_Key=sa1_.Site_Key 
inner join Profit_Centers pca3_ 
    on sa1_.Site_Key=pca3_.ProfCtr_Site_Key 
left outer join Sites_WF_Configuration swcfg2_ 
    on sa1_.Site_Key=swcfg2_.SiteWFCfg_Site_Key 
WHERE this_.SiteWFInfo_Effective_Date <= @p0 
    and @p1 <= this_.SiteWFInfo_End_Date 
    and pca3_.ProfCtr_Open_Date <= @p2 
    and @p3 < coalesce(pca3_.ProfCtr_Close_Date, @p4) 
    and this_.SiteWFInfo_TimeCapRule_Key > @p5

Answer 1

如果我理解正确，我们需要将left （当前属性投影） 替换为effDate 常量投影。那我们就可以这样做了

// instead of this
// var left = Projections.Property<DateTime>(effDate);

// we would use this
// DateTime effDate is passed in
var effDate = DateTime.Today.Date; // C#'s today
var left = Projections.Constant(effDate);

而且，我们应该切换 （更改顺序） 我们的“COALESCE”，因为属性应该首先出现：Coalesce(ProfCtr_Close_Date, '6/6/2079')

var right = Projects.SqlFunction("COALESCE",
    NHibernateUtil.DateTime,

    // As DOC of COALESCE says:
    // "Evaluates the arguments in order and returns the current value of 
    //  the first expression that initially does not evaluate to NULL."

    Projections.Property<ProfitCenter>(pc => pc.CloseDate), 
    Projections.Constant(DateTime.Parse("6/6/2079").DateNHibernateUtil.DateTime)
    );

最后，我们应该为连接的列使用相同的别名。让我们稍微调整一下主查询：

var foo = CurrentSession().QueryOver<Site>(() => sa)
    .Inner.JoinQueryOver<ProfitCenter>(() =>  sa.ProfitCenter, () => pca)
    .Where(restriction)

右侧也应该使用pca

var right = Projects.SqlFunction("COALESCE",
    NHibernateUtil.DateTime,
    // be sure that column goes to correct table
    // ==> use the same alias
    Projections.Property(() => pca.CloseDate), 
    Projections.Constant(DateTime.Parse("6/6/2079").DateNHibernateUtil.DateTime)
    );