Question

我有多个SQL服务器表，我想从中提取数据并写入XML。我希望我的XML形成如下：

 <Data>
     <Query1Table>
          <Table>
              <Column1>Data</Column1>
              <Column2>Data</Column2>
              ...
          </Table>
      </Query1Table>
      <Query2Table>
          <Table>
              <Column1>Data</Column1>
              <Column2>Data</Column2>
              ...
          </Table>
      </Query2Table>
   </Data>

我使用数据集来编写xml，但是我使用的代码并没有附加数据，它会覆盖：

        Dim connetionString As String
        Dim connection As SqlConnection
        Dim adapter As SqlDataAdapter
        Dim directory As String
        Dim ds As New DataSet
        Dim sql As String

        connection = New SqlConnection(connetionString)
        sql = "select * from scheduledata"
        connection.Open()
        adapter = New SqlDataAdapter(sql, connection)
        adapter.Fill(ds)

        ds.DataSetName = "Schedule"
        ds.WriteXml(directory)

        ds.Clear()
        sql = "select * from costdata"
        adapter = New SqlDataAdapter(sql, connection)
        adapter.Fill(ds)
        ds.WriteXml(directory)

我尝试通过一次调用SQL查询将它全部添加到同一数据集中，但这并不能帮助在XML中将它们分开 - 它将它们分组在同一节点中。

如果有人有好的建议，我会采用不同的方法。

Answer 1

您已将directory定义为字符串，因此ds.WriteXml将（创建并）按该名称写入文件。

改为使用FileStream或XmlTextWriter。

Answer 2

我写入.xml文件（有效）的方式如下

Private Sub AuthenticationContinuebtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles AuthenticationContinuebtn.Click

    On Error GoTo PasswordHandler

    GlobalVariables.Username = Usernametxtbx.Text
    GlobalVariables.Password = Passwordtxtbx.Text
    GetUsernamePassword()
    Close()
    Exit Sub
    PasswordHandler:
    MsgBox("Incorrect password or username.")
End Sub


Private Sub UserAuthenticationWindow_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    Dim FileName4 As String = "C:\Forte\UsernamePassword.xml"
    Dim FileRead4 As XmlTextReader = New XmlTextReader("C:\Forte\UsernamePassword.xml")

    'If statement to see if file exists.
    If System.IO.File.Exists(FileName4) = True Then

        Do While (FileRead4.Read)
            Select Case FileRead4.NodeType

                Case XmlNodeType.Text, XmlNodeType.Element

                    If FileRead4.Name = "Username" Then
                        FileRead4.Read()
                        Usernametxtbx.Text = FileRead4.Value
                        GlobalVariables.Username = Usernametxtbx.Text
                    End If
                    If FileRead4.Name = "Password" Then
                        FileRead4.Read()
                        Passwordtxtbx.Text = FileRead4.Value
                        GlobalVariables.Password = Passwordtxtbx.Text
                    End If
            End Select
        Loop
    Else
        MainBox.MainTextBox.AppendText(FileName4 & " could not be found. Settings are restored to defaults.")
        MainBox.Logging(Date.Now & FileName4 & " could not be found. Settings are restored to defaults.")
    End If
    FileRead4.Close()
End Sub

Public Sub createNode3(ByVal Username As String, ByVal Password As String, ByVal writer As XmlTextWriter)

    'On Error Resume Next
    writer.WriteStartElement("Username_Password")
    writer.WriteStartElement("Username")
    writer.WriteString(Username)
    writer.WriteEndElement()
    writer.WriteStartElement("Password")
    writer.WriteString(Password)
    writer.WriteEndElement()
    writer.WriteEndElement()

End Sub

将多个SQL Server表作为单独的节点写入XML Document

2 个答案: