黑客可以删除我使用下面功能的服务器文件和数据库吗？ [重复]

I want to know how to protect my website from hacker. I am a php-mysql developer. For fetching data from database i always use mysqli. For prevent my website from sql injection i always use $db->real_esacpe_string() function of php. For prevent my website from XSS(Cross site scripting) i used this function

function parsing($text)
{
global $db;
        $text=$db->real_escape_string($text);
 $text= @trim($text);
       $text= strip_tags($text);
 if(get_magic_quotes_gpc()) {
            $text= stripslashes($text);
        }
    $text=str_replace('<','',$text);
    $text=str_replace('>','',$text);   
       $text=htmlspecialchars($text, ENT_QUOTES, 'UTF-8');
    return($text);
}
$name=parsing($_POST['name']);

Any suggestion from your side is welcomed. Thanks in advance.

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With all of does done i don't think a hacker can delete or access your database.

But there are also many other techniques a hacker can use in hacking your website.

Like

1. DDOS
2. XSS
3. SESSION Hyjacking etc

Which there are also different ways of protecting your website against them.