mysql vb.net 中用于更新查询的正确语法是什么？

Question

this is my sample code

        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

when I clicked the button an exception appears saying

You have an error in your sql syntax; check the manual that corresponds to your mysql server version for the right syntax to use near 's breakthrough to challenge yesterday's old pattern, and to create tomorrow's n' at line 1

Answer 1

The problem is that you're using reader = command.ExecuteReader on UPDATE statement with concatenated argument string. You should use ExecuteNonQuery with parameterized query like this:

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: ExecuteReader used to return query results from SELECT statement, ie SELECT * FROM itss.announcement WHERE idAnno = 3 .