Question

在Fluent NHibernate中使用Oracle和QueryOver时，我遇到了算术溢出错误，因为SelectAvg正在输出一个带有许多小数位的值。我认为，由于小数位数过多，因此无法在C＃中将此数字映射为双精度值。

这是我的NHibernate代码：

var queryOverResult = _session.QueryOver<PurchasedVehicle>(() => purchasedVehicle)
                .JoinAlias(() => purchasedVehicle.FinancialSnapshot, () => financialSnapshot)
                .Where(pv => pv.Created >= startDate)
                .Where(pv => pv.Created <= endDate)
                .SelectList(list => list
                    .SelectCount(pv => pv.Dealer.Id).WithAlias(() => topPerformersKpiDto.PurchaseCount)
                    .SelectAvg(() => financialSnapshot.LikeMineDaysSupply).WithAlias(() => topPerformersKpiDto.AverageLms)
                    .SelectAvg(() => financialSnapshot.CostToMarket).WithAlias(() => topPerformersKpiDto.AverageCtm)
                    .SelectGroup(pv => pv.Dealer.Id))

运行时出现此错误：

"InnerException": {
    "Message": "An error has occurred.",
    "ExceptionMessage": "Arithmetic operation resulted in an overflow.",
    "ExceptionType": "System.InvalidCastException",
    "StackTrace": "   at Commons.Data.XDataReader.GetValueSafely(Int32 i)\r\n   at NHibernate.Type.NullableType.NullSafeGet(IDataReader rs, String name)\r\n   at NHibernate.Loader.Criteria.CriteriaLoader.GetResultColumnOrRow(Object[] row, IResultTransformer customResultTransformer, IDataReader rs, ISessionImplementor session)\r\n   at NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies)\r\n   at NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies)\r\n   at NHibernate.Loader.Loader.DoList(ISessionImplementor session, QueryParameters queryParameters)",
    "InnerException": {
      "Message": "An error has occurred.",
      "ExceptionMessage": "Arithmetic operation resulted in an overflow.",
      "ExceptionType": "System.OverflowException",
      "StackTrace": "   at Oracle.DataAccess.Types.DecimalConv.GetDecimal(IntPtr numCtx)\r\n   at Oracle.DataAccess.Client.OracleDataReader.GetDecimal(Int32 i)\r\n   at Oracle.DataAccess.Client.OracleDataReader.GetValue(Int32 i)\r\n   at Commons.Data.XDataReader.GetValueSafely(Int32 i)"
    }

topPerformersKpiDto.AverageLms和topPerformersKpiDto.AverageCtm都是double类型。

public class TopPerformersKpiDto : IDto
{
    public Guid DealerId { get; set; }  
    public int PurchaseCount { get; set; }  
    public double? AverageLms { get; set; } 
    public double? AverageCtm { get; set; }
}

NHibernate产生此oracle sql：

SELECT y0_,
       y1_,
       y2_,
       y3_
FROM   (SELECT Count(this_.dealerid)                                          AS
               y0_,
               Avg(Cast(financials1_.likeminedayssupply AS DOUBLE PRECISION)) AS
               y1_,
               Avg(Cast(financials1_.costtomarket AS DOUBLE PRECISION))       AS
               y2_,
               this_.dealerid                                                 AS
               y3_
        FROM   omni.purchasedvehicles this_
               INNER JOIN omni.purchasedvehiclesnapshots financials1_
                       ON this_.id = financials1_.purchasedvehicleid
        WHERE  this_.created >= :p0
               AND this_.created <= :p1
        GROUP  BY this_.dealerid
        ORDER BY y0_ desc)
WHERE  rownum <= :p2

运行此命令时，平均属性的值类似于“ 78.58731195652173913043478260869565217391”。

我正在尝试的一种解决方法是将平均值转换为“ Decimal（0，3）”，如下所示：

               y0_,
               Cast(Avg(Cast(financials1_.likeminedayssupply AS DOUBLE PRECISION)) as Decimal(10,3)) AS
               y1_,
               Cast(Avg(Cast(financials1_.costtomarket AS DOUBLE PRECISION)) as Decimal(10,3))       AS

当我在sql中执行此操作时，一切正常。但是，我不知道如何在NHibernate的QueryOver上下文中做到这一点。

编辑：看起来错误是我遇到的错误与这里的错误相同：https://community.oracle.com/thread/329112我不知道如何在NHibernate中截断我的号码。

这也似乎与我尝试在.NET中代表NUMBER（38）的问题有关：Which .NET data type is best for mapping the NUMBER Oracle data type in NHibernate?

在NHibernate中使用SelectAvg时出现“算术运算导致溢出”错误

0 个答案: