Защита от SQL-инъекций

$arrs=array('_GET','_POST','_COOKIE');
foreach($arrs as $arr_key=>$arr_value){
	if(is_array($$arr_value)){
		foreach($$arr_value as $key=>$value){
			$nbz1=substr_count($value,'--');
			$nbz2=substr_count($value,'/*');
			$nbz3=substr_count($value,"'");
			$nbz4=substr_count($value,'"');
			if($nbz1>0||$nbz2>0||$nbz3>0||$nbz4>0){
				Print404();
				exit(); 
			}
		}
	}
}