Question

一些背景知识。我们创建了一个名为SqlSum的类型。它有2个属性，Id和SumValue。

我在同一个会话中有两个查询：

SqlSum paidTemp = session.CreateSQLQuery(
    "select count(p.id) as Id, Sum(p.PaymentAmount) as SumValue " +
    "FROM StPayments p " +
    "where p.Active = 1 and p.IsVoided = 0 and p.StCustomerFk = :custid")
    .AddEntity(typeof(SqlSum))
    .SetParameter("custid", cust.Id)
    .List<SqlSum>().First();
if (paidTemp != null)
{
    paid = paidTemp.SumValue;
}

SqlSum allocTemp = session.CreateSQLQuery(
    "select count(pA.id) as Id, Sum(pA.Amount) As SumValue " +
    "FROM StPaymentAllocations pA " +
    "INNER JOIN StPayments p on pA.StPaymentFk = p.Id " +
    "where pA.Active = 1 and p.StCustomerFk = :custid")
    .AddEntity(typeof(SqlSum))
    .SetParameter("custid", cust.Id)
    .List<SqlSum>().First();
if (allocTemp != null)
{
    allocated = allocTemp.SumValue;
}

我可以在分析器中清楚地看到paytemp的查询返回的是1575的和值，而allocTemp查询返回的值是1500，但是，付费和分配的变量都被赋值为1575.实际上，检查调试器中allocTemp.SumValue属性的值显示为1575。

现在，我进行了一些小的更改，并将每个查询都移到了自己的会话中：

using (var session = factory.OpenSession())
using (var trans = session.BeginTransaction(IsolationLevel.ReadCommitted))
{
    SqlSum paidTemp = session.CreateSQLQuery(
        "select count(p.id) as Id, Sum(p.PaymentAmount) as SumValue " +
        "FROM StPayments p " +
        "where p.Active = 1 and p.IsVoided = 0 and p.StCustomerFk = :custid")
        .AddEntity(typeof(SqlSum))
        .SetParameter("custid", cust.Id)
        .List<SqlSum>().First();
    if (paidTemp != null)
    {
        paid = paidTemp.SumValue;
    }
    trans.Commit();
    session.Flush();
}    

using (var session = factory.OpenSession())
using (var trans = session.BeginTransaction(IsolationLevel.ReadCommitted))
{
    SqlSum allocTemp = session.CreateSQLQuery(
        "select count(pA.id) as Id, Sum(pA.Amount) As SumValue " +
        "FROM StPaymentAllocations pA " +
        "INNER JOIN StPayments p on pA.StPaymentFk = p.Id " +
        "where pA.Active = 1 and p.StCustomerFk = :custid")
        .AddEntity(typeof(SqlSum))
        .SetParameter("custid", cust.Id)
        .List<SqlSum>().First();
    if (allocTemp != null)
    {
        allocated = allocTemp.SumValue;
    }
    trans.Commit();
    session.Flush();
}

执行此代码时，突然alloctemp.SumValue按预期为1500.

是什么导致第二个查询在第一个示例中保留第一个查询的值？

Answer 1

如果您的Id列值可以返回相同的值，那么第一级缓存已经认为此ID在其中，并且duplicate行。

因此： -

如果您想将Id作为一列保留，请转换为dto，记住要覆盖Equals和GetHashCode。例如see this exmple
不要使用列名Id（老实说我不确定这个名称）。

为什么我的第一个查询的值是从第二个查询返回的值？

1 个答案: