How to update my database?

private void update_Click(object sender, EventArgs e)
{
    try
    {
        string con = @"Data Source=|DataDirectory|\students.sdf;Persist Security Info = True";
        SqlCeConnection conn = new SqlCeConnection(con);
        conn.Open();
        string command = "update info_ash SET name = @Name; roll = @Roll; hometown=@HomeTown;twitter=@twitter;birth_year=@Birth_Year;birth_month=Birth_Month; birth_Date = @Birth_Date; b_g = @Blood_Group; religion = @Religion; facebook = @Facebook_id; mobile = @Contact_no; email = @email; where id='" + search.Text + "'";
        SqlCeCommand cmd = new SqlCeCommand(command, conn);
        cmd.Parameters.AddWithValue("@Name", name.Text);
        cmd.Parameters.AddWithValue("@Roll", roll.Text);
        cmd.Parameters.AddWithValue("@Birth_Date", birth_date.Text);
        cmd.Parameters.AddWithValue("@Blood_Group", blood_group.Text);
        cmd.Parameters.AddWithValue("@Birth_Month", birth_month.Text);
        cmd.Parameters.AddWithValue("@Birth_Year", birth_year.Text);
        cmd.Parameters.AddWithValue("@Religion", religion.Text);
        cmd.Parameters.AddWithValue("@Facebook_id", facebook.Text);
        cmd.Parameters.AddWithValue("@Contact_no", mobile.Text);
        cmd.Parameters.AddWithValue("@HomeTown", home_town.Text);
        cmd.Parameters.AddWithValue("@email", email.Text);
        cmd.Parameters.AddWithValue("@twitter", twitter.Text);
        cmd.ExecuteNonQuery();
        MessageBox.Show("Update Successfully Accomplished.");
        conn.Close();
    }
    catch
    {
        MessageBox.Show("Error occured");
    }