NHibernate.StaleStateException : Unexpected row count: 0; expected: 1

Question

HL Guys，

我正在为现有系统编写后端管理程序。我选择了NHibernate作为我的数据访问解决方案，并且对它来说还很陌生。我在 parent /子女关系中遇到以下错误:

NHibernate.StaleStateException : Unexpected row count: 0; expected: 1

该错误是由以下事实引起的:在我的源代码中，我将新的子对象添加到MeetingAdministrators的父级子级集合中。保存父对象时，我希望还添加子对象，但是仅为父对象生成INSERT。 Nhibernate不会为子代生成INSERT，而是尝试更新子代，即使该子代不存在也是如此。因此，它会显示上面显示的错误消息。我在网上和nhibernate文档中到处都找到了这种情况，但没有找到任何帮助。大多数代码都涉及不属于主键的外键，或者人们似乎正在处理一对一或多对多的关系。我需要指定映射和代码，以便在插入父项时也插入子项。请帮忙。

我的数据结构如下:

session –父表

MeetingID(pk)(int，身份)

说明

StartDate

IsActive

地点

MeetingAdministrator –子表

MeetingID(pk，fk)

AdminNetworkID(pk)(varchar)

DateCreated

IsActive

这是Visual Basic .NET源代码:

<Serializable()> _
Public Class MeetingAdministrator

    Private _MeetingID As Integer
    Public Overridable Property MeetingID() As Integer
        Get
            Return _MeetingID
        End Get
        Set(ByVal value As Integer)
            _MeetingID = value
        End Set
    End Property

    Private _AdminNetworkID As String
    Public Overridable Property AdminNetworkID() As String
        Get
            Return _AdminNetworkID
        End Get
        Set(ByVal value As String)
            _AdminNetworkID = value
        End Set
    End Property

    Private _IsActive As Byte
    Public Overridable Property IsActive() As Byte
        Get
            Return _IsActive
        End Get
        Set(ByVal value As Byte)
            _IsActive = value
        End Set
    End Property

    Private _DateCreated As Date
    Public Overridable Property DateCreated() As Date
        Get
            Return _DateCreated
        End Get
        Set(ByVal value As Date)
            _DateCreated = value
        End Set
    End Property

    Private _LastModified As Date
    Public Overridable Property LastModified() As Date
        Get
            Return _LastModified
        End Get
        Set(ByVal value As Date)
            _LastModified = value
        End Set
    End Property

    Private _meeting As Meeting
    Public Overridable Property Meeting() As Meeting
        Get
            Return _meeting
        End Get
        Set(ByVal value As Meeting)
            _meeting = value
        End Set
    End Property

    Public Overrides Function Equals(ByVal obj As Object) As Boolean
        Return MyBase.Equals(obj)
    End Function

    Public Overrides Function GetHashCode() As Integer
        Return MyBase.GetHashCode()
    End Function

End Class




Imports Iesi.Collections
Imports Iesi.Collections.Generic



Public Class Meeting

    Private _MeetingID As Integer
    Private _Description As String

    Public Overridable Property MeetingID() As Integer
        Get
            Return _MeetingID
        End Get
        Set(ByVal value As Integer)
            _MeetingID = value
        End Set
    End Property

    Public Overridable Property Description() As String
        Get
            Return _Description
        End Get
        Set(ByVal value As String)
            _Description = value
        End Set
    End Property

    Private _StartDate As Date = Now
    Public Overridable Property StartDate() As Date
        Get
            Return _StartDate
        End Get
        Set(ByVal value As Date)
            _StartDate = value
        End Set
    End Property

    Private _IsActive As Byte
    Public Overridable Property IsActive() As Byte
        Get
            Return _IsActive
        End Get
        Set(ByVal value As Byte)
            _IsActive = value
        End Set
    End Property

    Private _DateCreated As Date
    Public Overridable Property DateCreated() As Date
        Get
            Return _DateCreated
        End Get
        Set(ByVal value As Date)
            _DateCreated = value
        End Set
    End Property

    Private _Venue As String
    Public Overridable Property Venue() As String
        Get
            Return _ Venue
        End Get
        Set(ByVal value As String)
            _ Venue = value
        End Set
    End Property

    Private _meetingAdministrator As ISet(Of MeetingAdministrator)
    Public Overridable Property MeetingAdministrators() As ISet(Of MeetingAdministrator)
        Get

            Return _meetingAdministrator
        End Get
        Set(ByVal value As ISet(Of MeetingAdministrator))
            _meetingAdministrator = value
        End Set
    End Property

    Public Overridable Sub AddAdministrator(ByVal meetingAdministrator As MeetingAdministrator)
        meetingAdministrator.Meeting = Me

        _meetingAdministrator.Add(meetingAdministrator)
    End Sub


    Public Sub New()
        _meetingAdministrator = New HashedSet(Of MeetingAdministrator)()

    End Sub
End Class

这是映射文件:

<!-- Meeting.hbm.xml -->
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="Data"
                    namespace="Data.Domain" >

  <!-- Mapping Information -->
  <class name="Meeting"  table="Meeting" >
    <id name="MeetingID" column="MeetingID" type="int">
      <generator class="identity" />
    </id>
    <property name="Description" />
    <property name="StartDate" />
    <property name="IsActive" />
    <property name="Venue" />
    <set name="MeetingAdministrators" table="MeetingAdministrator" inverse="true"  lazy="true"  cascade="save-update"  access="property" >
      <key column="MeetingID"  foreign-key="MeetingID"  />
      <one-to-many class="Meeting"  />
    </set>
  </class>
</hibernate-mapping>

<!-- MeetingAdministrator.hbm.xml -->
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="Data"
                    namespace="Data.Domain" >

  <!-- Mapping Information -->
  <class name="MeetingAdministrator"  table="MeetingAdministrator" >
    <composite-id>
      <key-property  name="AdminNetworkID"  column="AdminNetworkID"  type="string"  >
      </key-property>
      <key-many-to-one name="Meeting" class="Meeting" >
        <column name="MeetingID" />
      </key-many-to-one>
    </composite-id>
    <property name="IsActive" />
    <property name="DateCreated" />
  </class>
</hibernate-mapping>

Answer 1

我很确定您需要在<version/>类中添加MeetingAdministrator属性，以使其正常工作。有关更多讨论，请参见this article。