Question

我有一个.Net应用程序链接到具有这样的用户定义类型的Oracle数据库：

create or replace TYPE Person as object (firstname varchar2(50),lastname varchar2(50));

UDT在应用程序级别具有以下对象：

<OracleCustomTypeMapping("SCHEMA.PERSON")>
Public Class Person
    Implements IOracleCustomType
    Implements IOracleCustomTypeFactory
    Implements INullable

    Private FirstName_ As String

    <OracleObjectMapping("FIRSTNAME")>
    Public Property FirstName As String
        Get
            Return FirstName_
        End Get
        Set(value As String)
            FirstName_ = value
            IsNull_ = False
        End Set
    End Property


    Private LastName_ As String

    <OracleObjectMapping("LASTNAME")>
    Public Property LastName As String
        Get
            Return LastName_
        End Get
        Set(value As String)
            LastName_ = value
            IsNull_ = False
        End Set
    End Property

    Public Sub New()
        IsNull_ = True
    End Sub

    Public Sub FromCustomObject(Connection As OracleConnection, Pointer As IntPtr) Implements IOracleCustomType.FromCustomObject
        OracleUdt.SetValue(Connection, Pointer, "FIRSTNAME", FirstName)
        OracleUdt.SetValue(Connection, Pointer, "LASTNAME", LastName)
    End Sub

    Public Sub ToCustomObject(Connection As OracleConnection, Pointer As IntPtr) Implements IOracleCustomType.ToCustomObject
        FirstName = CStr(OracleUdt.GetValue(Connection, Pointer, "FIRSTNAME"))
        LastName = CStr(OracleUdt.GetValue(Connection, Pointer, "LASTNAME"))

        IsNull_ = False
    End Sub

    Public Function CreateObject() As IOracleCustomType Implements IOracleCustomTypeFactory.CreateObject
        Return New Person
    End Function

    Public ReadOnly Property IsNull As Boolean Implements INullable.IsNull
        Get
            Return IsNull_
        End Get
    End Property

    Private IsNull_ As Boolean = True
End Class

应用程序对象与数据库对象之间的通信运行良好。我可以从数据库加载数据，但是当尝试将数据保存回数据库时，出现错误：没有为此对象定义无参数构造函数。我不知道此错误的出处，因为我的对象确实具有无参数的构造函数。

我尝试使用DataAdapter将数据返回保存到数据库中。

'Load data from database
Command = New OracleCommand("Select * from MyTable", Connection)
Command.CommandType = CommandType.Text
DataAdapter = New OracleDataAdapter(Command)
DataAdapter.FillSchema(DataSet, SchemaType.Source, "MyTable")
DataAdapter.Fill(DataSet, "MyTable")
DataTable = DataSet.Tables("MyTable")

'Make some change
'Change some rows values
'...

'Save databack to the database
DataAdapter.Update(DataTable)   '<<<< Where the error is raised

这是堆栈跟踪：

  Stack trace:
   at System.Data.Common.DbDataAdapter.UpdatedRowStatusErrors(RowUpdatedEventArgs rowUpdatedEvent, BatchCommandInfo[] batchCommands, Int32 commandCount)
   at System.Data.Common.DbDataAdapter.UpdatedRowStatus(RowUpdatedEventArgs rowUpdatedEvent, BatchCommandInfo[] batchCommands, Int32 commandCount)
   at System.Data.Common.DbDataAdapter.Update(DataRow[] dataRows, DataTableMapping tableMapping)
   at Oracle.DataAccess.Client.OracleDataAdapter.Update(DataRow[] dataRows, DataTableMapping tableMapping)
   at System.Data.Common.DbDataAdapter.UpdateFromDataTable(DataTable dataTable, DataTableMapping tableMapping)
   at System.Data.Common.DbDataAdapter.Update(DataTable dataTable)

有人知道如何解决吗？

谢谢，欢呼声

错误：没有为此对象定义无参数构造函数

0 个答案: