PHP database connection class

First build a MySQL class library... suiting the requirements like in this sample piece:

<?php

include '../config/Dbconfig.php';

class Mysql extends Dbconfig {

    public $connectionString;
    public $dataSet;
    private $sqlQuery;
    
    protected $databaseName;
    protected $hostName;
    protected $userName;
    protected $passCode;

    function Mysql() {
        $this -> connectionString = NULL;
        $this -> sqlQuery = NULL;
        $this -> dataSet = NULL;

        $dbPara = new Dbconfig();
        $this -> databaseName = $dbPara -> dbName;
        $this -> hostName = $dbPara -> serverName;
        $this -> userName = $dbPara -> userName;
        $this -> passCode = $dbPara ->passCode;
        $dbPara = NULL;
    }
  
    function dbConnect()    {
        $this -> connectionString = mysql_connect($this -> serverName,$this -> userName,$this -> passCode);
        mysql_select_db($this -> databaseName,$this -> connectionString);
        return $this -> connectionString;
    }

    function dbDisconnect() {
        $this -> connectionString = NULL;
        $this -> sqlQuery = NULL;
        $this -> dataSet = NULL;
        $this -> databaseName = NULL;
        $this -> hostName = NULL;
        $this -> userName = NULL;
        $this -> passCode = NULL;
    }

    function selectAll($tableName)  {
        $this -> sqlQuery = 'SELECT * FROM '.$this -> databaseName.'.'.$tableName;
        $this -> dataSet = mysql_query($this -> sqlQuery,$this -> connectionString);
        return $this -> dataSet;
    }

    function selectWhere($tableName,$rowName,$operator,$value,$valueType)   {
        $this -> sqlQuery = 'SELECT * FROM '.$tableName.' WHERE '.$rowName.' '.$operator.' ';
        if($valueType == 'int') {
            $this -> sqlQuery .= $value;
        }
        else if($valueType == 'char')   {
            $this -> sqlQuery .= "'".$value."'";
        }
        $this -> dataSet = mysql_query($this -> sqlQuery,$this -> connectionString);
        $this -> sqlQuery = NULL;
        return $this -> dataSet;
        #return $this -> sqlQuery;
    }


    function insertInto($tableName,$values) {
        $i = NULL;

        $this -> sqlQuery = 'INSERT INTO '.$tableName.' VALUES (';
        $i = 0;
        while($values[$i]["val"] != NULL && $values[$i]["type"] != NULL) {
            if($values[$i]["type"] == "char") {
                $this -> sqlQuery .= "'";
                $this -> sqlQuery .= $values[$i]["val"];
                $this -> sqlQuery .= "'";
            }
            else if($values[$i]["type"] == 'int') {
                $this -> sqlQuery .= $values[$i]["val"];
            }
            $i++;
            if($values[$i]["val"] != NULL)  {
                $this -> sqlQuery .= ',';
            }
        }
        $this -> sqlQuery .= ')';
        #echo $this -> sqlQuery;
        mysql_query($this -> sqlQuery,$this ->connectionString);
        return $this -> sqlQuery;
        #$this -> sqlQuery = NULL;
    }

    function selectFreeRun($query) {
        $this -> dataSet = mysql_query($query,$this -> connectionString);
        return $this -> dataSet;
    }

    function freeRun($query) {
        return mysql_query($query,$this -> connectionString);
    }
}
?>

and the configuration file...

<?php
class Dbconfig {
    protected $serverName;
    protected $userName;
    protected $passCode;
    protected $dbName;

    function Dbconfig() {
        $this -> serverName = 'localhost';
        $this -> userName = 'root';
        $this -> passCode = 'pass';
        $this -> dbName = 'dbase';
    }
}
?>

You can use custom database class.
Code :

<?php 
Class Database
{
    private $user ;
    private $host;
    private $pass ;
    private $db;

    public function __construct()
    {
        $this->user = "root";
        $this->host = "localhost";
        $this->pass = "";
        $this->db = "db_blog";
    }
    public function connect()
    {
        $link = mysql_connect($this->user, $this->host, $this->pass, $this->db);
        return $link;
    }
}
?>

Alright, one piece of advice:

Do everything for a reason. Don't use things you don't know. Go and learn them instead.

One may give you an answer for this specific question, but until you don't know what Object Oriented means and why there are classes at all, you shouldn't use them.