Attendance Database Design

protected void Repeater2_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item ||
             e.Item.ItemType == ListItemType.AlternatingItem)
    {
        HiddenField hfUserid = (e.Item.FindControl("hfUser") as HiddenField);
        MySqlConnection conn = new MySqlConnection(ConfigurationManager.ConnectionStrings["sql354211ConnectionString"].ConnectionString);
        MySqlCommand command = new MySqlCommand("select idattendance,present from attendance where iduser=@userid and idclasslesson=@classlessonid", conn);
        command.Parameters.AddWithValue("userid", hfUserid.Value.ToString());
        command.Parameters.AddWithValue("classlessonid", 6);
        try
        {
            conn.Open();
            MySqlDataAdapter dat = new MySqlDataAdapter(command);
            DataTable ds = new DataTable();
            dat.Fill(ds);
            DataView dv = new DataView(ds);
            Repeater r = ((Repeater)e.Item.FindControl("repeatPresent"));
            r.DataSource = dv;
            r.DataBind();
        }
        catch { Response.Write("<h3>Something Bad Happened During database connection. Refresh the page</h3>"); }
        finally { conn.Close(); }
        //Bind the add button here.
    }

}

protected void btnUpdate_Click(object sender, EventArgs e)
{
    foreach (RepeaterItem masteritem in Repeater2.Items)
    {
        Repeater r = ((Repeater)masteritem.FindControl("repeatPresent"));
        foreach (RepeaterItem item in r.Items)
        {
            string pr = ((TextBox)item.Controls[3]).Text;
            string id = ((HiddenField)item.Controls[1]).Value;
            if (item.ItemType == ListItemType.Item || item.ItemType == ListItemType.AlternatingItem)
            {
                MySqlConnection conn = new MySqlConnection(ConfigurationManager.ConnectionStrings["sql354211ConnectionString"].ConnectionString);
                MySqlCommand command = new MySqlCommand("update attendance set present="+pr+" where idattendance="+id , conn);
                try
                {
                    conn.Open();
                    command.ExecuteNonQuery();
                    //////////testing place
                    /*
                    string a = ((TextBox)item.Controls[3]).Text;
                    string b = ((HiddenField)item.Controls[1]).Value;
                    Response.Write("<h2>" + a.ToString() + " - " + b.ToString() + "</h2>");*/
                }
                catch { }
                finally { conn.Close(); }
            }
        }
    }
}

<table>
<asp:Repeater ID="Repeater2" runat="server" OnItemDataBound="Repeater2_ItemDataBound" DataSourceID="SqlDataSource1">
    <HeaderTemplate>
    </HeaderTemplate>
    <FooterTemplate>
        </table>
    </FooterTemplate>
    <ItemTemplate>
        <tr>
            <th style="width: 150px">
                <asp:Label ID="lblUser" runat="server" Text='<%#Eval("iduser").ToString()+Eval("name").ToString() %>'></asp:Label><asp:HiddenField ID="hfUser" runat="server" Value='<%#Eval("iduser") %>' />
            </th>
            <asp:Repeater ID="repeatPresent" runat="server">
                <ItemTemplate>
                    <th style="width: 30px">
                        <asp:HiddenField ID="hfAttendid" runat="server" Value='<%#Eval("idattendance") %>' />
                        <asp:TextBox Width="20px" Height="20px" Font-Size="X-Small" ID="txtPresent" runat="server" Text='<%# Eval("present") %>'></asp:TextBox></th>
                </ItemTemplate>
            </asp:Repeater>
        </tr>
    </ItemTemplate>
</asp:Repeater>
<asp:LinkButton ID="btnUpdate" runat="server" class="btn btn-primary" CausesValidation="True" Text="KAYDET" OnClick="btnUpdate_Click" />
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:sql354211ConnectionString %>" ProviderName="<%$ ConnectionStrings:sql354211ConnectionString.ProviderName %>" SelectCommand="SELECT DISTINCT attendance.iduser,name, idclasslesson FROM attendance inner join user on user.iduser=attendance.iduser WHERE (idclasslesson = 6)"></asp:SqlDataSource>

CREATE TABLE `attendance` (
  `idattendance` int(11) NOT NULL AUTO_INCREMENT,
  `iduser` int(11) DEFAULT NULL,
  `idclasslesson` int(11) DEFAULT NULL,
  `attenddate` date DEFAULT NULL,
  `present` int(11) DEFAULT '0',
  `excuse` varchar(45) COLLATE utf8_turkish_ci DEFAULT NULL,
  PRIMARY KEY (`idattendance`)
) ENGINE=InnoDB AUTO_INCREMENT=50 DEFAULT CHARSET=utf8 COLLATE=utf8_turkish_ci;