Question

I am new to PHP-> first time developer. I am working on my web application and it is nearly done; nevertheless, most of my sql was done directly via code using direct mysql requests. This is the way I approached it:

In classes_db.php I declared the db settings and created methods that I use to open and close DB connections. I declare those objects on my regular pages:

class classes_db {

    public $dbserver = 'server;
    public $dbusername = 'user';
    public $dbpassword = 'pass';
    public $dbname = 'db';

    function openDb() {
        $dbhandle = mysql_connect($this->dbserver, $this->dbusername, $this->dbpassword);
        if (!$dbhandle) {
            die('Could not connect: ' . mysql_error());
        }
        $selected = mysql_select_db($this->dbname, $dbhandle)
                or die("Could not select the database");

        return $dbhandle;
    }


    function closeDb($con) {
        mysql_close($con);
    }
}

On my regular page, I do this:

<?php
require 'classes_db.php';
session_start();

//create instance of the DB class
$db = new classes_db();

//get dbhandle
$dbhandle = $db->openDb();

//process query
$result = mysql_query("update user set username = '" . $usernameFromForm . "' where iduser= " . $_SESSION['user']->iduser);

//close the connection
if (isset($dbhandle)) {
    $db->closeDb($dbhandle);
}

?>

My questions is: how to do it right and make it OO and secure? I know that I need incorporate prepared queries-> how to do it the best way? Please provide some code

Answer 1

stop using mysql_* , use mysqli and PDO instead

PHP PDO vs normal mysql_connect

mysql_* functions are getting old. For a long time now mysql_* has
been at odds with other common SQL database programming interfaces. It
doesn’t support modern SQL database concepts such as prepared
statements, stored procs, transactions etc… It’s method for escaping
parameters with mysql_real_escape_string and concatenating into SQL
strings is error prone and old fashioned. The other issue with mysql_*
is that it has had a lack of attention lately from developers, it is
not being maintained… Which could mean things like security
vulnerabilities are not getting fixed, or it may stop working
altogether with newer versions of MySQL. Also lately PHP community
have seen fit to start a soft deprecation of mysql_* which means you
will start seeing a slow process of eventually removing mysql_*
functions altogether from the language (Don’t worry this will probably
be awhile before it actually happens!).

PDO has a much nicer interface, you will end up being more productive,
and write safer and cleaner code. PDO also has different drivers for
different SQL database vendors which will allow you to easily use
other vendors without having to relearn a different interface. (though
you will have to learn slightly different SQL probably). Instead of
concatenating escaped strings into SQL, in PDO you bind parameters
which is an easier and cleaner way of securing queries. Binding
parameters also allow for a performance increase when calling the same
SQL query many times with slightly different parameters. PDO also has
multiple methods of error handling. The biggest issue I have seen with
mysql_* code is that it lacks consistent handling, or no handling at
all! With PDO in exception mode, you can get consistent error handling
which will end up saving you loads of time tracking down issues.

PDO is enabled by default in PHP installations now, however you need
two extensions to be able to use PDO: PDO, and a driver for the
database you want to use like pdo_mysql. installing the MySQL driver
is as simple as installing the php-mysql package in most
distributions.

http://wiki.hashphp.org/PDO_Tutorial_for_MySQL_Developers