มือใหม่หัดขับ Oop php ครับ พอดีลองเขียน Class Connect sql แล้ว Query error

mysql_select_db("project1") or die (mysql_error());

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<?php

class mySQL{

  var $host;
  var $username;
  var $password;
  var $database;
  public $dbh;  //Variable for storing connection

  public function connect($set_host, $set_username, $set_password, $set_database){
    $this->host = $set_host;
    $this->username = $set_username;
    $this->password = $set_password;
    $this->database = $set_database;

    $this->dbh = mysql_connect($this->host, $this->username, $this->password)or die("cannot connect"); //Store data connection specifier in object
	mysql_query("SET NAMES UTF8");
	mysql_query("SET character_set_results=utf8");
	mysql_query("SET character_set_client=utf8");
	mysql_query("SET character_set_connection=utf8");
    mysql_select_db($this->database)or die("cannot select DB");

  }

  public function query($sql)
  {
       return mysql_query($sql,$this->dbh);  //Specify connection handler when doing query
  }

  public function fetch($sql)
  {
       return mysql_fetch_array($this->query($sql));
  }

}
$connect = new mySQL();
$connect->connect('localhost', 'root', '', 'project1');
$settings_query = mysql_query("SELECT * FROM member", $connect->dbh); //Specify connection handler when doing query
$settings = mysql_fetch_array($settings_query);

//With query method in object you can do this:    
$settings_query = $connect->query("SELECT * FROM member");  //Use object method to query
$settings = mysql_fetch_array($settings_query);

//with fetch method in object you can just do this:
$settings = $connect->fetch("SELECT * FROM member");

//echo $settings['test']; 

?>

mysql_select_db( $idb_name,$this->ilink );

<?php
error_reporting(E_ALL); // คำสั่งแสดงผลที่มีการ Error ออกมา
class _MySql
{
	//connect sql
	private $ihost;
	private $iuser;
	private $ipass;
	private $idb_name;
	private $ilink; // เก็บค่า Connect MySQL
	
	//mysql_query
	private $_res;
	
	//mysql_fetch_array
	private $_fetch_array = array();	
	
	public function _ConnectSQL ($ihost , $iuser , $ipass , $idb_name) // รับค่า Connect Database
	{
		$this->ihost 	= $ihost; 		// hosting
		$this->iuser 	= $iuser; 		// username database hosting
		$this->ipass 	= $ipass; 		// password database hosting
		$this->idb_name = $idb_name; 	// database name hosting
		
		$this->ilink = mysql_connect( $this->ihost , $this->iuser , $this->ipass );
		mysql_query ("SET NAMES UTF8");
		mysql_query("SET character_set_results=utf8");
		mysql_query("SET character_set_client=utf8");
		mysql_query("SET character_set_connection=utf8");
		mysql_select_db( $idb_name,$this->ilink );
		//echo "Test Connect OK";
		
	}
	
	public function _QuerySQL ($strrs) // Msql_Query
	{
		return $this->_res = mysql_query($strrs);
	}
	
	public function _Num_Rows_SQL () // Mysql_Num_Rows
	{
		return mysql_num_rows($this->_res);	
	}
	
	public function _Fetch_Array_SQL() // Mysql_Fetch_Array()
	{
		if ( count ( $this->_fetch_array ) > 0 ) // นับจำนวน _fetch_array ถ้าเท่ากับ 0 แสดงว่ามีค่าตัวแปร ถ้ามากว่า 0 แสดงว่าไม่มีค่าตัวแปร
		{
			return $this->_fetch_array;
		}
		else
		{
			while ( $row = mysql_fetch_array($this->_res) )
			{
				$this->_fetch_array[] = $row;	// เก็บ _fetch_array เป็น Arrya โดยรับค่าจาก $row
			}
			
			return $this->_fetch_array;
		}
		
		//return mysql_fetch_array ($this->_res);
	}
	
	public function _CloseSQL()
	{
		return mysql_close($this->ilink);
	}
	
}

$obj=new _MySql();
$obj->_ConnectSQL('localhost','root','','project1');
$obj->_QuerySQL("select * from member") or die (mysql_error());
echo $obj->_Num_Rows_SQL() or die (mysql_error());
print_r ($obj->_Fetch_Array_SQL()) or die (mysql_error());
$obj->_CloseSQL() or die (mysql_error());
?>