Question

我正在使用vb和.net 2.0构建一个asp.net Web应用程序。我有一个处理对象及其所有属性的类。此类正确处理数据库的读取，创建和删除。但是，它不会更新。我直接从Microsoft SQL数据库中获取了更新脚本，但我无法弄清楚。这是我的SQL命令。

saveCommand = "UPDATE [Database].[Table] SET [name] = @name,[content] = @content,[date_updated] = @dateupdated WHERE ref = @ref"

然后将其放入......

Dim setCmd As New SqlCommand(saveCommand, sqlConn)

然后将参数值放入其中。这很奇怪，因为“saveCommand”是根据项目是否已经存在（更新）还是不存在来确定的（切换到“INSERT INTO”命令可以工作）

更多代码

Public Class MyClass()
    #Region Properties
        Public name As String = ""
        Public content As String = ""
        Public date_updated As DateTime = DateTime.Now
    #End Region

    Public Sub Save()
    Dim sqlConn As New SqlConnection(sqlConnString)

    sqlConn.Open()

    Dim saveCommand As String
    If Me.Exists Then
        saveCommand = "UPDATE [Database].[Table] SET [name] = @name,[content] = @content,[date_updated] = @date_updated WHERE ref = @ref"
    Else
        saveCommand = "INSERT INTO [Database].[Table] ([name],[content],[date_updated],[ref]) VALUES(@name,@content,@date_updated,@ref)"
    End If

    Dim setCmd As New SqlCommand(saveCommand, sqlConn)
    setCmd.Parameters.Add("@name", Data.SqlDbType.VarChar).Value = Me.name
    setCmd.Parameters.Add("@content", Data.SqlDbType.VarChar).Value = Me.content
    setCmd.Parameters.Add("@date_updated", Data.SqlDbType.DateTime).Value = Me.date_updated

    If Me.Exists Then
        setCmd.Parameters.Add("@ref", Data.SqlDbType.Int).Value = Me.ID
    Else
        Dim countCmd As New SqlCommand("SELECT COUNT(*) FROM [DWM-DataSQL].[dbo].[biglots]", sqlConn)
        Me.ID = countCmd.ExecuteScalar() + 1
        setCmd.Parameters.Add("@ref", Data.SqlDbType.Int).Value = Me.ID
        Me.Exists = True
    End If

    setCmd.ExecuteNonQuery()
    sqlConn.Close()
    sqlConn.Dispose()
End Sub

Public Sub New()
End Sub

Public Sub New(ByVal num As Integer)
    Me.ID = num
End Sub

End Class

这是由

召集的

myObj = New BLL.MyClass(ref)

'When form is submitted
Public Sub submitForm(ByVal sender As Object, ByVal e As System.EventArgs)
   myObj.name = tbName.Text
   myObj.content = tbcontent.Text
   myObj.Save()
End Sub

Answer 1

我明白了。它以某种方式在save（）函数之前调用read（）函数RIGHT，因此它替换了所有值。谢谢，无论如何

VB.NET更新SQL数据库命令

1 个答案: