mysql vb.net中更新查詢的正確語法是什麼？

Question

這是我的示例代碼

 Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
     myConn = New MySqlConnection 
    myConn.ConnectionString = "server=localhost;userid=root;password=root;database=itss" 
    Dim reader As MySqlDataReader 

    Try 
     myConn.Open() 
     Dim query As String 
     query = "update itss.announcement set annoMessage = '" & TextBox1.Text & "' where idAnno = 3" 
     command = New MySqlCommand(query, myConn) 
     reader = command.ExecuteReader 
     myConn.Close() 
    Catch ex As Exception 
     MessageBox.Show(ex.Message) 
    Finally 
     myConn.Dispose() 
    End Try 
    'strMessage = TextBox1.Text 
    Form1.GroupBox1.Select() 
    Form1.Activate() 
    Form4.Activate() 
    Me.Hide() 
End Sub 

當我點擊出現異常的按鈕說

您的SQL語法錯誤;檢查對應於你的MySQL服務器版本使用附近的正確語法手冊的突破，挑戰昨天的舊格局，創造未來的N'位於第1行

Answer 1

的問題是，你使用reader = command.ExecuteReader上帶連接參數字符串的UPDATE語句。您應該使用ExecuteNonQuery與參數化查詢是這樣的：

myConn.Open() 
Dim query As String 
query = "update itss.announcement set annoMessage = @message where idAnno = 3" 
command = New MySqlCommand(query, myConn) 
command.Parameters.Add("@message", MySqlDbType.VarChar).Value = TextBox1.Text 
reader = command.ExecuteNonQuery() ' this is used for UPDATE statement 
myConn.Close() 

NB：用於從SELECT語句返回查詢結果ExecuteReader，即SELECT * FROM itss.announcement WHERE idAnno = 3。