[PHP] simple registration script

[HTML]

 <?php

/*
* Register class written and updated by HTML AKA: TONY.
* Soon to replace simple if's with ternary..
* added a verify email part, username length and table variable.
*/

class register{

//Setting up Variables, you can add more, for example terms of service, age, verify_email, etc.

private $_username;
private $_password;
private $_email;
private $_verify_email;

//mysql fields
private $_table;
private $_namefield;
private $_passfield;
private $_mailfield;


//Giving the variables values
    function __construct($u_name, $p_word, $e_mail, $v_mail)
    {
        $this->_username = $u_name;
        $this->_password = $p_word;
        $this->_email = $e_mail;
        $this->_verify_email = $v_mail;
    }  

//checks to make sure fields are set
    public function Run()
    {
        if(empty($this->_username) || empty($this->_password) || empty($this->_email) || empty($this->_verify_email))
        {
        
            echo "All fields are required to continue!";
        }
 
        else
            
        {   
            $this->Username_length();
            $this->checkEmail();
            $this->verifyEmail();
            $this->_mysql_check();
        }
   
     }

//Checks username length
    public function Username_length()
    {
     echo ( strlen($this->_username) < 4 ? "Your username must be at least 4 letters long!" : null );
      exit();
    }
    
    
    
//check for @ sign in an email.
    public function checkEmail()
    {
        
      if( strpos($this->_email, '@') === false )
      {
        exit("Your email address is missing '@'");
      }
    
    }


//Lets make sure the emails are matched.    
    public function verifyEmail()
    {
       echo ($this->_email != $this->_verify_email ? "Your email's don't match." : null );
       exit();
    }



// Set up the mysql_fields you needs.
    public function mysql_fields($n_field, $p_field, $e_field, $table)
    {
       $this->_namefield = $n_field;
       $this->_passfield = $p_field;
       $this->_mailfield = $e_field;
       $this->_table = $table;
    }

//checks to see if the username and email exist in the database
    private function _mysql_check()
    {
        $query = mysql_query("SELECT * FROM $this->_table WHERE '$this->_namefield' = '$this->_username' OR $this->_mailfield = '$this->_email' ");
        if (mysql_num_rows($query) != 0)
        {
            echo "Username or email address already exists!";
            
        }
   
        else
        {
            $this->_mysql_insert();   
        }

    }

//inserts values
    private function _mysql_insert()
    {
        $sql = "INSERT INTO $this->_table
          (
          $this->_namefield,
          $this->_passfield,
          $this->_mailfield
          ) 

          VALUES 
          ('$this->_username',
           '$this->_password',
           '$this->_email'
          )";

          $register = mysql_query($sql);
          
          
    }



}

?>  

[HTML]

Update 001:
Added a mysql class so that you will be able to change the database values thanks to Chris letting me know I should.

[HTML]

Update 002:
Added a new variable for mysql fields called table (forgot to add in 001)
Added verification of email and a check to make sure the email addresses match each other.
Added a username check function which will make sure the username is at least 4 characters long.