There's 1 way to Insert
items into the XMLDB:
Insert Items
Syntax: public function insertItem($id = null, $attributes = null, $childs = null, $table)
Example:
$xmldb = new XMLDB('db.xml');
$xmldb->insertItem('test', array('name'=>'alright'), array('visibility'=>'true', 'x'=>'33'), 'table1')
This will insert the following item into table1
$id
can now be null and must be null if you use autoincrement. It will return false
otherwise.
<item id="test" name="alright">
<visibility>true</visibility>
<x>33</x>
</item>