Bugs and Suggestions

using (SqlConnection conn = new SqlConnection())
            {
                //prepare conectio string
                conn.ConnectionString = "server='servername';database=D_MART;IntegratedSecurity=True";

                try
                {
                    // Prepare SQL command that we want to query

                     SqlCommand cmd = new SqlCommand();
                    cmd.CommandType = CommandType.Text;
                    // cmd.CommandText = "SELECT * FROM MYTABLE"
                    cmd.CommandText = "SELECT PRODUCT_ID FROM PRODUCT_DETAILS";
                    cmd.Connection = conn;
                    // open database connection.
                    conn.Open();

                    Console.WriteLine("Connection open!");
                    //Execute the query 
                    SqlDataReader sdr = cmd.ExecuteReader();
                    //Retrieve data from table and Display result
                    while(sdr.Read())
                    {
                        int PRODUCT_ID = (int)sdr["id"];
                        Console.WriteLine(PRODUCT_ID);

                    }
                    //Close Connection
                    conn.Close();                    
                }
                catch(Exception ex)
                {
                    Console.WriteLine("can not open connection!");
                }
            }
        }