I have posted an earlier version of this and here is the improved version from the feedback I recieved. Some of the feedback I received was;

• Don't chain method (tried my best to limit this)
• Do not use print() or die() and an error response (still a little lost, but I did attempt to use a redirect to a custom error page)

I tried my best to rewrite the code, I am still very new to this so go easy. I did read up on OOP methodology and read about Interfacing and Implementation, so I tried to incorporate that in my class.

I would love to see some different ideas on how to make this the most efficient as possible. I am sure it needs a ton of changing, but that is why I am here to help me learn and grow. I am a visual learner so if possible actual code would be awesome, but any response would be greatly appreciated.

<?php
class Mysql
{
        private $user;
        private $pass;
        private $data;
        private $host;
        
        public function __construct($user,$pass,$data,$host)
        {
                $this->user = $user;
                $this->pass = $pass;
                $this->data = $data;
                $this->host = $host;
                $this->process();
        }
        
        /* INTERFACE */
        private function process()
        {
                if($this->verifyNullFields()==true)
                {
                        if($this->verifyDatabaseConnection()==true)
                        {
                                if($this->verifyDatabaseExist()==true)
                                {
                                        print('ALL PASSED'); //for debugging
                                }
                                else
                                {
                                        print('redirect to custom error page will go here');
                                }
                        }
                        
                        else
                        {
                                  print('redirect to custom error page will go here');
                        }

                }
                else
                {
                        print('redirect to custom error page will go here');
                }
        }
        
        /* IMPLEMENTATIONS */
        private function verifyNullFields()
        {
                if($this->user != NULL)
                {
                        if($this->data != NULL)
                        {
                                if($this->host != NULL)
                                {
                                        return true;
                                }
                                else
                                {
                                        return false;
                                }

                        }
                        else
                        {
                                return false;
                        }
                }
                else
                {
                        return false;
                }
        }
        private function verifyDatabaseConnection()
        {
                $link = @mysql_connect($this->host,$this->user,$this->pass);
                if(!$link)
                {
                        return false ;
                }
                else
                {
                        return true;
                }
        }
        private function verifyDatabaseExist()
        {
                $db = @mysql_select_db($this->data);
                if(!$db)
                {
                        return false;
                }
                else
                {
                        return true;
                }
        }
}
?>
<?php
$m = new Mysql("root","","magic","localhost");
?>