php中实现xml与mysql数据相互转换的方法

<?php 
class MySQL2XML { 
        protected $conn; 
        protected $result; 
        protected $tables; 
        protected $saveFolder = 'datas/'; 
         
        public function __construct($config = NULL) { 
                if($config !== NULL && is_array($config)) { 
                        $this->connect($config); 
                } 
        } 
         
        public function connect($config) { 
                $this->conn = mysql_connect($config['host'], $config['username'], $config['password']); 
                if($this->conn) { 
                        mysql_select_db($config['database']); 
                        return true; 
                } 
                return false; 
        } 
         
        public function setSaveFolder($folder) { 
                if(is_dir($folder)) { 
                        $this->saveFolder = rtrim(str_replace("/", "/", $folder),'/'); 
                        return true; 
                } 
                return false; 
        } 
         
        public function setTables($tables) { 
                if(is_array($tables)) { 
                        $this->tables = $tables; 
                        return true; 
                } 
                return false; 
        } 
         
        public function query($query) { 
                if(!isset($query) || trim($query) == '') return false; 
                $this->result = mysql_query($query); 
                if($this->result) return true; 
                return false; 
        } 
         
        public function toXML() { 
                if(!isset($this->tables)) return false; 
                foreach($this->tables as $table) { 
                        $file = $this->saveFolder.$table.'.xml'; 
                        $fp = @fopen($file, 'w'); 
                        if(!$fp) exit('Can not write file'); 
                        fwrite($fp, $this->tableToXML($table)); 
                        fclose($fp); 
                        unset($fp); 
                } 
                return true; 
        } 
         
        public function tableToXML($table) { 
                header("content-type:text/xml;charset=utf-8"); 
                $xml = "<?xml version="1.0" encoding="utf-8" ?>n<datas>n"; 
                $fields = $this->getFields($table); 
                $datas = $this->getDatas($table); 
                $cdata = array(); 
                foreach($datas as $data) { 
                        foreach($data as $key => $value) 
                                $cdata[$key][] = $value; 
                } 
                foreach($fields as $element) { 
                        $xml .= "t<fields name="{$element['Field']}" type="{$element['Type']}" null="{$element['Null']}" key="{$element['Key']}" default="{$element['Default']}" extra="{$element['Extra']}">n"; 
                        foreach($cdata[$element['Field']] as $value) { 
                                $xml .= "tt<data>{$value}</data>n"; 
                        } 
                        $xml .= "t</fields>n"; 
                } 
                $xml .= '</datas>'; 
                return $xml; 
        } 
         
        protected function getFields($table) { 
                $query = "SHOW FIELDS FROM {$table}"; 
                $this->query($query); 
                return $this->fetchAll(); 
        }
         
        protected function getDatas($table) { 
                $query = "SELECT * FROM {$table}"; 
                $this->query($query); 
                return $this->fetchAll(); 
        } 
         
        protected function fetch() { 
                if(is_resource($this->result)) { 
                        return mysql_fetch_assoc($this->result); 
                } 
                return false; 
        } 
         
        protected function fetchAll() { 
                if(is_resource($this->result)) { 
                        $return = array(); 
                        $row = NULL; 
                        while($row = mysql_fetch_assoc($this->result)) { 
                                $return[] = $row; 
                        } 
                        return $return; 
                } 
                return false; 
        } 
} 
?>

<?php 
$xml = new MySQL2XML(array('host'=>'localhost', 'username'=>'root', 'password'=>'', 'database'=>'mysql')); 
$xml->setTables(array('wp_term_relationships','wp_terms'));//设置备份的表 
$xml->setSaveFolder('datas/');//保存备份文件的文件夹 
$xml->toXML();//备份开始 
?>