Question

I am working on something. I am trying to Create a class in config.php that contains a method to connect to the database.In dbConnectExample.php, instantiate that class and call the method. I am kinda getting confused because I am learning to others programming classes too. This is what I have so far;

    <?php # Scripts 6.3 - Rectangle.php

Class Rectangle {

//Declare the attributes:
public $width = 0;
public $height = 0;

//Method to set the dimensions.
Function set_size($w = 0, $h = 0) {
        $this->width = $w;
        $this->height = $h;
}

//Method to calculate and return the area.
function get_area() {
    return ($this->width * $this->height);
    }

// Method to calculate and return the perimeter.
function get_perimeter() {
    return ( ( $this->width + $this->height) * 2 );
    }

    //Method to determine if the rectangle
    //is also a square
    function is_square() {

    if ($this->width == $this->height) {
    return true; //Square
    } else {
        return false; //Not a square
    }
  }

} //End of Rectangle class.

I know I am creating a class with a method. I am just confused to connect to a database you go like this;

    //Connect to the database
$DBConnect = @new mysqli("localhost", "valerie_2shuawna", "norris");
if (mysqli_connect_errno())
      die("<p>Unable to connect to the database server.</p>"
      . "<p>Error code " . mysqli_connect_errno()
      . ": " . mysqli_connect_error()) . "</p>";
$DBName = "config.php";
    @$DBConnect->select_db($DBName)
         Or die("<p>Unable to select the database.</p>"
         . "<p>Error code " . mysqli_errno($DBConnect)
         . ": " . mysqli_error($DBConnect)) . "</p>";

$DBConnect->close();

But I am suppose to instantiate that class and call the method. and then the config it is suppose to contain a method to connect to the database. If someone can help me figure out what I am doing wrong and maybe explain so I am not so confused I would be grateful it.

Answer 1

You can create a simple class:

// Database.php

class Database
{
    public static function getDbo($dbName)
    {
        $dbo = new mysqli("localhost", "user", "password");

        if (mysqli_connect_errno()) {
            throw new Exception(
                "<p>Unable to connect to the database server.</p>"
               . "<p>Error code " . mysqli_connect_errno()
               . ": " . mysqli_connect_error()) . "</p>"
            );
        }

        if (!$dbo->select_db($dbName)) {
            throw new Exception(
                "<p>Unable to select the database.</p>"
                . "<p>Error code " . mysqli_errno($DBConnect)
                . ": " . mysqli_error($DBConnect)) . "</p>"
            );
        }

        return $dbo;
    }
}

// SomeFile.php

require_once 'Database.php';

try {
    $dbo = Database::getDbo();

    // If I made it this far then I can start querying
    $dbo->query('SELECT stuff FROM table');

    // etc.

} catch (Exception $e) {
    die($e->getMessage());
}