php对xml进行简单的增删改查（CRUD）操作

假如有下面xml文件：

<?xml version="1.0" encoding="UTF-8"?>setting1 valuesetting2 valuesetting3 value     ....    ....    ....

// CREATE$config = new SimpleXmlElement('');$config->setting1 = 'setting1 value';         $config->saveXML('config.xml');               // READ$config = new SimpleXmlElement('config.xml');echo $config->setting1;echo $config->asXml();// UPDATE$config->setting1 = 'new value';$config->setting2 = 'setting2 value';echo $config->asXml();// DELETEunset($config->setting1);$config->setting2 = NULL;echo $config->asXML();unlink('config.xml');