Rewriting Old MySQL-PHP Code with Deprecated mysql_* Functions

As PHP evolves, certain functions become deprecated, including the mysql_* commands. To enhance security and stability, these commands should be replaced with prepared statements and PDO.

Key Replacements:

• Replace mysql_connect with PDO::__construct().
• Replace mysql_select_db with setting the database name in the PDO connection string, e.g., mysql:host=127.0.0.1;dbname=people.

Code Sample:

 // Old deprecated code
$db = new dbConn('127.0.0.1', 'root', 'pass', 'people', 'animals');

 // New PDO code
$db = new PDO('mysql:host=127.0.0.1;dbname=people;charset=UTF-8', 'root', 'pass');

Additional Considerations:

• Constructor and Destructor: The __construct() and __destruct() functions are not necessary with PDO, as it handles connection and closing internally.
• Database Selection: Database selection is now embedded in the PDO connection string. Use the dbname parameter in the connection string to specify the desired database.

Example Class:

The following example class demonstrates how to rewrite the selectDb method using PDO:

class DB
{
    private $pdo;

    public function __construct($host, $db, $user, $pass)
    {
        // Establish PDO connection
        $this->pdo = new PDO("mysql:host=$host;dbname=$db;charset=UTF-8", $user, $pass);
    }

    public function selectDatabase($dbName)
    {
        // No longer required with PDO
    }
}

Conclusion:

By replacing deprecated mysql_* functions with prepared statements and PDO, developers can enhance the security and stability of their code while simplifying database interactions.