如果记录存在更新，否则插入sql vb.net

Question

我有以下问题，我正在使用vb.net开发一个诊所应用程序，医生可以使用复选框checkbox2.text =“过敏” textbox15.text添加医疗信息。我要插入过敏记录，我想插入记录如果患者的FileNo（Textbox2.text）不存在，则仅更新注释，到目前为止，单击3次按钮后我仍然可以更新它，我不知道为什么？

任何帮助表示赞赏:)预先感谢

    Dim connection3 As New SqlClient.SqlConnection
    Dim command3 As New SqlClient.SqlCommand
    Dim adaptor3 As New SqlClient.SqlDataAdapter
    Dim dataset3 As New DataSet
    connection3.ConnectionString = ("Data Source=(LocalDB)\v11.0;AttachDbFilename=" + My.Settings.strTextbox + ";Integrated Security=True;Connect Timeout=30")
    command3.CommandText = "SELECT ID,Type FROM Medical WHERE FileNo='" & TextBox2.Text & "';"
    connection3.Open()
    command3.Connection = connection3
    adaptor3.SelectCommand = command3
    adaptor3.Fill(dataset3, "0")
    Dim count9 As Integer = dataset3.Tables(0).Rows.Count - 1
    If count9 > 0 Then
        For countz = 0 To count9
            Dim A2 As String = dataset3.Tables("0").Rows(countz).Item("Type").ToString
            Dim B2 As Integer = dataset3.Tables("0").Rows(countz).Item("ID")
            TextBox3.Text = A2
            If A2 = CheckBox1.Text Then
                Dim sql4 As String = "update Medical set MNotes=N'" & TextBox22.Text & "' where FileNo='" & TextBox2.Text & "' and Type = '" & CheckBox1.Text & "' and ID='" & B2 & "';"
                Dim cmd4 As New SqlCommand(sql4, connection3)
                Try
                    cmd4.ExecuteNonQuery()
                Catch ex As Exception
                    MsgBox(ex.Message)
                End Try
            ElseIf A2 = CheckBox2.Text Then
                Dim sql4 As String = "update Medical set MNotes=N'" & TextBox15.Text & "' where FileNo='" & TextBox2.Text & "' and Type = '" & CheckBox2.Text & "' and ID='" & B2 & "';"
                Dim cmd4 As New SqlCommand(sql4, connection3)
                Try
                    cmd4.ExecuteNonQuery()
                Catch ex As Exception
                    MsgBox(ex.Message)
                End Try
            End If
        Next
    Else
        If CheckBox1.Checked = True Then
            Dim sql4 As String = "insert into Medical values('" & CheckBox1.Text & "',N'" & TextBox22.Text & "','" & TextBox2.Text & "')"
            Dim cmd4 As New SqlCommand(sql4, connection3)
            Try
                cmd4.ExecuteNonQuery()
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try
        End If
        If CheckBox2.Checked = True Then
            Dim sql4 As String = "insert into Medical values('" & CheckBox2.Text & "',N'" & TextBox15.Text & "','" & TextBox2.Text & "')"
            Dim cmd4 As New SqlCommand(sql4, connection3)
            Try
                cmd4.ExecuteNonQuery()
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try
        End If

    End If

Answer 1

我认为您的问题之一可能与您将表行的数量减少1，然后在0以上进行测试有关：

Dim count9 As Integer = dataset3.Tables(0).Rows.Count - 1
If count9 > 0 Then

尝试更改为：

Dim count9 As Integer = dataset3.Tables(0).Rows.Count
If count9 > 0 Then

另外，请确保在代码后面提到的复选框之一（ CheckBox1或CheckBox2 ）被打勾。

-编辑-

抱歉-没有解释原因！ 原因是.NET中大多数与数组/列表类似的结构都是基于零的（即从0开始而不是从1开始计数）。

Answer 2

对您来说，最好的做法是允许SQL执行最擅长的工作，从而最大程度地提高生产力。 假设您使用的是SQL Server 2008，则MERGE函数是满足您所提供条件的绝佳用例。

这是一个非常基本的示例，它是根据您的一些代码设计的：

CREATE PROCEDURE [dbo].[csp_Medical_Merge]
    @MType int, @FileNo varchar(20), @MNotes varchar(max), @ID int,  @OtherParams
AS
BEGIN

MERGE INTO [DatabaseName].dbo.Medical AS DEST
USING 
    ( 
        /*
            Only deal with data that has changed.  If nothing has changed,
            then move on.
        */
        SELECt @MType, @MNotes, @FileNo, @ID, @OtherParams
        EXCEPT
        Select [Type], MNotes, FileNo, ID, OtherFields from [DatabaseName].dbo.Medical
) As SRC ON SRC.ID = DEST.ID
WHEN MATCHED THEN
    UPDATE SET
        DEST.MNOTES = SRC.MNOTES,
        DEST.FileNo = SRC.FileNo,
        DEST.Type = SRC.Type
WHEN NOT MATCHED BY TARGET THEN
    INSERT (FieldsList) 
    VALUEs (FileNo, MNotes, etc, etc);

END
GO