把从SQL中取出的数据转化成XMl格式

　　
使用了php的PEAR和DB
<?php
// +----------------------------------------------------------------------+
// PHP version 4.0
// +----------------------------------------------------------------------+
// Copyright (c) 1997, 1998, 1999, 2000, 2001 The PHP Group
// +----------------------------------------------------------------------+
// This source file is subject to version 2.0 of the PHP license,
// that is bundled with this package in the file LICENSE, and is
// available at through the world-wide-web at
//
// If you did not receive a copy of the PHP license and are unable to
// obtain it through the world-wide-web, please send a note to
// +----------------------------------------------------------------------+
// Authors: Christian Stocker <chregu@phant.ch>
// +----------------------------------------------------------------------+
//
// $Id: sql2xml.php,v 1.59 2001/11/13 10:54:02 chregu Exp $

/**
* This class takes a PEAR::DB-Result Object, a sql-query-string or an array
*and returns a xml-representation of it.
*
* TODO
*-encoding etc, options for header
*-ERROR CHECKING
*
* Usage example
*
* include_once (DB.php);
* include_once(XML/sql2xml.php);
* $db = DB::connect(mysql://root@localhost/xmltest);
* $sql2xml = new xml_sql2xml();
* //the next one is only needed, if you need others than the default
* $sql2xml->setEncoding(ISO-8859-1,UTF-8);
* $result = $db->query(select * from bands);
* $xmlstring = $sql2xml->getXML($result);
*
* or
*
* include_once (DB.php);
* include_once(XML/sql2xml.php);
* $sql2xml = new xml_sql2xml(mysql://root@localhost/xmltest);
* $sql2xml->Add(select * from bands);
* $xmlstring = $sql2xml->getXML();
*
* More documentation and a tutorial/how-to can be found at
*
*
* @authorChristian Stocker <chregu@bitflux.ch>
* @version$Id: sql2xml.php,v 1.59 2001/11/13 10:54:02 chregu Exp $
* @packageXML
*/
class XML_sql2xml {

/**
* If joined-tables should be output nested.
*Means, if you have joined two or more queries, the later
*specified tables will be nested within the result of the former
*table.
*Works at the moment only with mysql automagically. For other RDBMS
*you have to provide your table-relations by hand (see user_tableinfo)
*
* @varboolean
* @see$user_tableinfo, doSql2Xml(), doArray2Xml();
*/
var $nested = True;

/**
* Name of the tag element for resultsets
*
* @varstring
* @seeinsertNewResult()
*/
var $tagNameResult = result;

/**
* Name of the tag element for rows
*
* @varstring
* @seeinsertNewRow()
*/
var $tagNameRow = row;

/**
*
* @varobject PEAR::DB
* @access private
*/
var $db = Null;


/**
* Options to be used in extended Classes (for example in sql2xml_ext).
* They are passed with SetOptions as an array (arrary(user_options = array());
*and can then be accessed with $this->user_options[bla] from your
*extended classes for additional features.
*This array is not use in this base class, its only for passing easy parameters
*to extended classes.
*
* @vararray
*/
var $user_options = array();


/**
* The DomDocument Object to be used in the whole class
*
* @varobjectDomDocument
* @accessprivate
*/
var $xmldoc;


/**
* The Root of the domxml object
* Im not sure, if we need this as a class variable....
* could be replaced by domxml_root($this->xmldoc);
*
* @varobject DomNode
* @accessprivate
*/
var $xmlroot;


/**
* This array is used to give the structure of your database to the class.
*Its especially useful, if you dont use mysql, since other RDBMS than
*mysql are not able at the moment to provide the right information about
*your database structure within the query. And if you have more than 2
*tables joined in the sql its also not possible for mysql to find out
*your real relations.
*The parameters are the same as in fieldInfo from the PEAR::DB and some
*additional ones. Here they come:
*From PEAR::DB->fieldinfo:
*
*$tableInfo[$i][table]: the table, which field #$i belongs to.
*for some rdbms/comples queries and with arrays, its impossible
*to find out to which table the field actually belongs. You can
*specify it here more accurate. Or if you want, that one fields
*belongs to another table, than it actually says (yes, theres
*use for that, see the upcoming tutorial ...)
*
*$tableInfo[$i][name]: the name of field #$i. if you want another
*name for the tag, than the query or your array provides, assign
*it here.
*
*Additional info
*$tableInfo[parent_key][$table]: index of the parent key for $table.
*this is the field, where the programm looks for changes, if this
*field changes, it assumes, that we need a new rowset in the
*parent table.
*
*$tableInfo[parent_table][$table]: name of the parent table for $table.
*
* @vararray
* @accessprivate
*/
var $user_tableInfo = array();

/**
* the encoding type, the input from the db has
*/
var $encoding_from= ISO-8859-1;

/**
* the encoding type, the output in the xml should have
* (note that domxml at the moment only support UTF-8, or at least it looks like)
*/
var $encoding_to = gb2312;

var $tagname = tagname;

/**
* Constructor
* The Constructor can take a Pear::DB data source name (eg.
*mysql://user:passwd@localhost/dbname) and will then connect
*to the DB, or a PEAR::DB object link, if you already connected
*the db before.
If you provide nothing as $dsn, you only can later add stuff with
*a pear::db-resultset or as an array. providing sql-strings will
*not work.
* the $root param is used, if you want to provide another name for your
*root-tag than root. if you give an empty string (), there will be no
*root element created here, but only when you add a resultset/array/sql-string.
*And the first tag of this result is used as the root tag.
*
* @parammixed $dsnPEAR::DB data source name or object DB object
* @paramstring $rootthe name of the xml-doc root element.
* @accesspublic
*/
function XML_sql2xml ($dsn = Null, $root = root) {

// if its a string, then it must be a dsn-identifier;

if (is_string($dsn))
{
include_once (DB.php);
$this->db = DB::Connect($dsn);
if (DB::isError($this->db))
{
print The given dsn for XML_sql2xml was not valid in file .__FILE__. at line .__LINE__.<br>\n;
return new DB_Error($this->db->code,PEAR_ERROR_DIE);
}

}

elseif (is_object($dsn) && DB::isError($dsn))
{
print The given param for XML_sql2xml was not valid in file .__FILE__. at line .__LINE__.<br>\n;
return new DB_Error($dsn->code,PEAR_ERROR_DIE);
}

// if parent class is db_common, then its already a connected identifier
elseif (get_parent_class($dsn) == db_common)
{
$this->db = $dsn;
}

$this->xmldoc = domxml_new_xmldoc(1.0);

//oehm, seems not to work, unfortunately.... does anybody know a solution?
$this->xmldoc->encoding = $this->encoding_to;

if ($root) {
$this->xmlroot = $this->xmldoc->add_root($root);
//PHP 4.0.6 had $root->name as tagname, check for that here...
if (!isset($this->xmlroot->{$this->tagname}))
{
$this->tagname = name;
}
}

}

/**
* General method for adding new resultsets to the xml-object
*Give a sql-query-string, a pear::db_result object or an array as
*input parameter, and the method calls the appropriate method for this
*input and adds this to $this->xmldoc
*
* @paramstring sql-string, or object db_result, or array
* @parammixed additional parameters for the following functions
* @accesspublic
* @seeaddResult(), addSql(), addArray(), addXmlFile()
*/
function add ($resultset, $params = Null)
{

// if string, then its a query, a xml-file or a xml-string...
if (is_string($resultset)) {
if (preg_match(/\.xml$/,$resultset)) {
$this->AddXmlFile($resultset,$params);
}
elseif (preg_match(/.*select.*from.*/i ,$resultset)) {
$this->AddSql($resultset);
}
else {
$this->AddXmlString($resultset);
}

}
// if array, then its an array...
elseif (is_array($resultset)) {
$this->AddArray($resultset);
}

if (get_class($resultset) == db_result) {
$this->AddResult($resultset);
}
}

/**
* Adds the content of a xml-file to $this->xmldoc, on the same level
* as a normal resultset (mostly just below <root>)
*
* @paramstring filename
* @parammixed xpatheither a string with the xpath expression or an array with xpath=>xpath expressionand root=tag/subtag/etc, which are the tags to be inserted before the result
* @accesspublic
* @seedoXmlString2Xml()
*/

function addXmlFile($file,$xpath = Null)
{
$fd = fopen( $file, r );
$content = fread( $fd, filesize( $file ) );
fclose( $fd );
$this->doXmlString2Xml($content,$xpath);
}

/**
* Adds the content of a xml-string to $this->xmldoc, on the same level
* as a normal resultset (mostly just below <root>)
*
* @paramstring xml
* @parammixed xpatheither a string with the xpath expression or an array with xpath=>xpath expressionand root=tag/subtag/etc, which are the tags to be inserted before the result
* @accesspublic
* @seedoXmlString2Xml()
*/