Error on .ExecuteNonQuery() in SQL Update Query [duplicate]

问题

I'm trying to update an Access database using a SQL query, whenever I click the save button, it generates an error

An unhandled exception of type 'System.Data.OleDb.OleDbException' occurred in System.Data.dll

Additional information: No value given for one or more required parameters.

And highlights .ExecuteNonQuery(). Can you guys help me on this? I'm new to vb.net.

Thanks in advance.

 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

回答1:

your query syntax is wrong. Since you are using params, use placeholders in the SQL: (the question marks are not some 'etc' type thing, you use ? to mark parameters!):

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

Note: Six parameters

' 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)

your missing 6th parameter:

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

I dont think Access supports named params, so you use dummy ones but be sure to AddWithValue in the order specified in the SQL string.

EDIT

You can just create a SQL string with the values embedded instead of using params which is sort of what your SQL string does. Params are much better (research SQL injection attacks), but your string method is wrong (and you cant mix methods). It should be:

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

The variables have to be outside the quotes or you will be setting FirstName to the literal "empFname"

来源：https://stackoverflow.com/questions/23185958/error-on-executenonquery-in-sql-update-query

标签

sql

vb.net

ms-access-2007