OOP in PHP - "__construct" connection

Question

Hey guys i am new to OOP and i am wanting to run two functions both requiring the same connection. I am struggling to declare the $mysqli variable in a way which will allow it to be used by both functions. I would rather just use the one as i will be adding many many more functions later. Any help greatly appreciated.

the error message i am receiving is;

Notice: Undefined variable: mysqli in C:\Users\PC\Documents\XAMPP\htdocs\test.php on line 13

<?php
class OOP 
{
function __construct(){
$mysqli = new mysqli('localhost', 'c3337015', 'c3337015', 'iitb');
if (mysqli_connect_errno()) {
        printf("Connect failed: %s\n", mysqli_connect_error());
        exit();
        }
    }

function getMember(){
        $stmt = $mysqli->prepare("SELECT First_Name FROM forum members");
        $stmt->execute();
        $stmt->store_result();
        $stmt->bind_result($First_Name);

        while ($row = $stmt->fetch()) {
        echo $First_Name;
        }

}
function getForum(){
        $stmt = $mysqli->prepare("SELECT ForumTitle FROM forum");
        $stmt->execute();
        $stmt->store_result();
        $stmt->bind_result($ForumTitle);

        while ($row = $stmt->fetch()) {
        echo $ForumTitle;
        }

}

}

your $mysqli scope is within the __construct so u may need to define a variable as public $mysqli and then in __construct use $this->mysqli and so in for other member functions. — Abhik Chakraborty
– Abhik Chakraborty, Commented Mar 14, 2014 at 18:34
I recommend to throw an exception instead of calling exit() in a class constructor. And also, you should change your database password, now that you've posted it to StackOverflow. — Bill Karwin
– Bill Karwin, Commented Mar 14, 2014 at 18:42

Chris Forrence · Accepted Answer · 2014-03-14 18:37:37Z

2

You're declaring $mysqli in your constructor, but it's not a class variable. You can simply add it as a class variable:

class OOP {
    private $mysqli;
    ...

Then any time you want to access the variable, replace $mysqli with $this->mysqli.

answered Mar 14, 2014 at 18:37

Chris Forrence

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Comments

lin · Accepted Answer · 2014-03-14 18:41:26Z

0

<?php
/**
 * My file
 * @author yourname
 *
 */
class OOP {

    /**  ============ class vars  ============ **/

    /**
     * DocBloc comment
     * @var mysqli
     */
    private $mysqli = null;



    /** ============ class methods ============ **/

    function __construct() 
    {

        $this->mysqli = new mysqli ( 'localhost', 'c3337015', 'c3337015', 'iitb' );

        if (mysqli_connect_errno ()) {
            printf ( "Connect failed: %s\n", mysqli_connect_error () );
            exit ();
        }
    }


    /*
     * DocBloc
     */
    function getMember() 
    {
        $stmt = $this->mysqli->prepare ( "SELECT First_Name FROM forum members" );
        $stmt->execute ();
        $stmt->store_result ();
        $stmt->bind_result ( $First_Name );

        while ( $row = $stmt->fetch () ) {
            echo $First_Name;
        }
    }


    /*
     * DocBloc
     */
    function getForum() 
    {
        $stmt = $this->mysqli->prepare ( "SELECT ForumTitle FROM forum" );
        $stmt->execute ();
        $stmt->store_result ();
        $stmt->bind_result ( $ForumTitle );

        while ( $row = $stmt->fetch () ) {
            echo $ForumTitle;
        }
    }
}

answered Mar 14, 2014 at 18:41

lin

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1 Comment

user3406014 Over a year ago

thank you very much for the easy to understand solution

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