/**
* Clears tree.
*
* Important!!!
* this method will destroy all data in the tree
*
* @param array|Axis_NSTree_Node $data
* @return int|Axis_NSTree_Node
*/
public function clear($data = array())
{
// delete structure .... oops
$this->_table->delete('');
if ($this->_2tables) {
// delete data ....oops
$this->_table2->delete('');
}
// create root
$columns = array($this->_left => 1, $this->_right => 2, $this->_level => 0);
$id = $this->_table->insert($columns);
// bind data
return $this->_bindNode($id, $data);
}