php中实现xml与mysql数据相互转换的方法

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" ?>nn";
$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) {
$xml .= "tt{$value}n";
}
$xml .= "tn";
}
$xml .= '';
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;
}
}
?>