Question

我正在尝试使用SQL查询更新Access数据库，每当我单击“保存”按钮时，它都会生成错误

System.Data.dll中出现未处理的“System.Data.OleDb.OleDbException”类型异常

附加信息：没有给出一个或多个必需参数的值。

并突出显示.ExecuteNonQuery()。你能帮助我吗？我是vb.net的新手。

提前致谢。

 Private Sub SaveButton_Click(sender As Object, e As EventArgs) Handles SaveButton.Click
        Dim empNum As String
        Dim empFname As String
        Dim empLname As String
        Dim empDept As String
        Dim empStat As String
        Dim empYears As String



        empNum = eNumText.Text
        empFname = empFnameText.Text
        empLname = empLnameText.Text
        empDept = DeptText.Text
        empStat = StatText.Text
        empYears = yearstext.Text

        con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source= c:\Databse\Company_db.accdb"
        con.Open()

        MsgBox(empNum)


        Dim SqlAdapter As New OleDbDataAdapter
        Dim Table As New DataTable

        Dim sqlQuery As String = "UPDATE tbl_empinfo SET EmpID='" & empNum & "', FirstName ='" & empFname & "', LastName='" & empLname & "', Department='" & empDept & "', Status='" & empStat & "', Years='" & empYears & "' WHERE EmpID ='" & empNum & "' "


        Using cmd As New OleDbCommand(sqlQuery, con)
            With cmd
                .CommandText = sqlQuery
                .Connection = con
                .Parameters.AddWithValue("EmpID", empNum)
                .Parameters.AddWithValue("FirstName", empFname)
                .Parameters.AddWithValue("LastName", empLname)
                .Parameters.AddWithValue("Department", empDept)
                .Parameters.AddWithValue("Status", empStat)
                .Parameters.AddWithValue("Years", empYears)
                .ExecuteNonQuery()
            End With
        End Using

        sqlQuery = "SELECT * FROM tbl_empinfo "
        Dim cmd1 As New OleDbCommand
        Dim da As New OleDbDataAdapter


        With cmd1
            .CommandText = sqlQuery
            .Connection = con
            With SqlAdapter
                .SelectCommand = cmd1
                .Fill(Table)
            End With
            With DataGridView1
                .DataSource = Table
            End With
        End With

        con.Close()
    End Sub

Answer 1

您的查询语法错误。由于您正在使用params，因此在SQL中使用占位符:(问号不是某些＆＃39;类型的东西，您使用?来标记参数！）：

Dim sqlQuery As String = "UPDATE tbl_empinfo SET FirstName = ?, 
             LastName=?, Department=?,
             Status=?, Years=? WHERE empID = ?"

注意：六个参数

' USING will dispose of the cmd when it is done with it
' ...can also set the SQL and connection props in the constructor:
Using cmd As New OleDbCommand(sqlQuery, con)
   With cmd
       ' no reason to move Textboxes to a variable either:
       .Parameters.AddWithValue("@p1", empFnameText.Text)
       .Parameters.AddWithValue("@p2", empLnameText.Text)
       .Parameters.AddWithValue("@p3", DeptText.Text)
       .Parameters.AddWithValue("@p4", StatText.Text)
       .Parameters.AddWithValue("@p5", yearstext.Text)

你缺少的第6个参数：

      .Parameters.AddWithValue("@p6", eNumText.Text)        
      .ExecuteNonQuery()
   End With
 End Using

我认为Access不支持命名参数，因此您使用虚拟参数，但请确保{SQL}字符串中指定的顺序为AddWithValue。

修改

您可以创建一个嵌入值的SQL字符串，而不是使用params，它是 sort 您的SQL字符串的作用。参数更好（研究SQL注入攻击），但你的字符串方法是错误的（你不能混合方法）。它应该是：

Dim sqlQuery As String = "UPDATE tbl_empinfo " & "SET FirstName = " & empFname & ", LastName=" & empLname

变量必须在引号之外，否则您将FirstName设置为文字＆＃34; empFname＆＃34;

SQL Update查询中的.ExecuteNonQuery（）出错

1 个答案: