Read Database Temperatures

<?php

  class Read_Database_Temperatures
  {
    public $mysqli;
    public $selected;

    public function __construct()
    {
      $db_name = "temperature";

      //
      // This program can be called with optional arguments:
      //   --database=foo         the name of the database to use
      //

      $options = getopt( "", [ "database::" ] );

      if( $options )
      {
        foreach( array_keys( $options ) as $key )
        {
          if( $key == "database" )
          {
            $db_name = $options[$key];
          }
        }
      }

      print( "<title>Using database $db_name</title>\n" );

      $this->mysqli = new mysqli( 'localhost', 'root', '', $db_name )
        or die( 'Could not connect: ' . mysqli_error() );

      $this->mysqli->select_db( $db_name )
          or die( "Could not select database $db_name" );

      $select = "SELECT id, mean, std_dev, reg_date FROM temps WHERE reg_date >= (CURTIME() - INTERVAL 1 MINUTE)";

      $this->selected = $this->mysqli->query( $select )
        or die( 'Select failed: ' . $this->mysqli->error() );
    }

    public function output()
    {
      if( $this->selected->num_rows > 0 )
      {
        print( "<table style='width: 100%'>\n" );
        print( "\t<tr>\n" );
        print( "\t\t<td>Record</td><td>Time</td>" );
        print( "<td>Temperature</td><td>Standard Deviation</td>\n" );
        print( "\t</tr>\n" );
        while( $row = $this->selected->fetch_assoc() )
        {
          print( "\t<tr>\n" );
          print( "\t\t<td>" . $row["id"] . "</td>  " );
          print( "<td>" . $row["reg_date"] . "</td>  " );
          print( "<td>" . $row["mean"] . "</td>  " );
          print( "<td>" . $row["std_dev"] . "</td>\n" );
          print( "\t</tr>\n" );
        }
        print( "</table>\n" );
      }
    }
  }

  $db = new Read_Database_Temperatures();
  $db->output();

?>