Question

我试图将文本框中的记录更新到Access数据库中，我想知道每次点击保存时都会产生错误

未处理的类型＆＃39; System.Data.OleDb.OleDbException＆＃39;发生在System.Data.dll
中
附加信息：没有给出一个或多个必需参数的值。

突出显示.ExecuteNonQuery()

这是什么意思？它阻止我运行我的代码：（

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()


        Dim SqlAdapter As New OleDbDataAdapter
        Dim Table As New DataTable

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

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

        Using cmd2 = New OleDbCommand(sqlQuery, con)
            cmd.Parameters.AddWithValue("FirstName", empFname)
            cmd.Parameters.AddWithValue("LastName", empLname)
            cmd.Parameters.AddWithValue("Department", empDept)
            cmd.Parameters.AddWithValue("Status", empStat)
            cmd.Parameters.AddWithValue("Years", empYears)
            cmd.ExecuteNonQuery()
        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

您正在尝试为适配器的SelectCommand设置UPDATE命令文本。这当然无法取得成功。最后但并非最不重要的是，UPDATE命令文本不包含WHERE子句，因此，如果执行，它将使用相同的数据更新表tbl_empinfo中的每条记录。

在此上下文中，不需要使用适配器。您可以简单地执行命令，提供适当的WHERE子句和其他参数的值

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

    Dim cmd As New OleDbCommand
    With cmd
        .CommandText = sqlQuery
        .Connection = con
        .Parameters.AddWithValue("@p1", empFName)
        .Parameters.AddWithValue("@p2", empLName)
        .Parameters.AddWithValue("@p3", empDept)
        .Parameters.AddWithValue("@p4", empStat)
        .Parameters.AddWithValue("@p5", empYears)
        .Parameters.AddWithValue("@p6", empNum)
        .ExecuteNonQuery()
    End With

在此之后，您可以调用重新加载数据的代码来填充网格

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

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

请注意，我已将命令和适配器的名称更改为较少混淆的名称。 SqlCommand和SqlDataAdapter是等同于OleDbCommand和OleDbDataAdapter但用于Sql Server的类的名称。乍一看，我以为您正在尝试使用SqlClient类来更新MS-Access数据库。

添加SQL QUERY STAT

1 个答案: