<p>Very nice work.</p>

<p>This is a great component that I can use on every project. </p>

<p>Two suggestions:</p>

<p>Perhaps the possible keys for the $_traversal array should be defined as class constants:<br />
so you could use:</p>

<p>protected $_traversal = array( <br />
self::TRAVERSAL_LEFT => 'lt', <br />
self::TRAVERSAL_RIGHT => 'rt', <br />
self::TRAVERSAL_COLUMN => 'row_id', <br />
self::TRAVERSAL_REF_COLUMN => 'parent_id' <br />
);</p>

<p>Also, perhaps there could also be a Zend_Db_Table_Row_Mptt (or would it be Zend_Db_Table_Mptt_Row?) that can define fetchAllDescendents(Zend_Db_Select $select = null) so that you don't have to pass the row into the table object to do so. Same with the delete(), fetchTree(), and fetchAllAncestors() methods.</p>

<ac:macro ac:name="code"><ac:plain-text-body><![CDATA[
<?php
class Zend_Db_Table_Mptt_Row extends Zend_Db_Table_Row_Abstract
{
/**

• Fetches all descendents of a given node
  *
• @param Zend_Db_Select $select - optional custom select object
• @return Zend_Db_Table_Rowset|null
  */
  public function fetchAllDescendents (Zend_Db_Select $select = null)
  Unknown macro: { return $this->getTable()->fetchAllDescendents($this, $select); }

/**

• Fetches all descendents of a given node and returns them as a tree
  *
• @param Zend_Db_Select $select - optional select object
• @return Zend_Db_Table_Rowset|null
  */
  public function fetchTree (Zend_Db_Select $select = null)
  Unknown macro: { return $this->getTable()->fetchTree($this, $select); }

/**

• Fetches all ancestors of a given node
  *
• @param Zend_Db_Select $select - optional custom select object
• @return Zend_Db_Table_Rowset|null
  */
  public function fetchAllAncestors (Zend_Db_Select $select = null)
  Unknown macro: { return $this->getTable()->fetchAllAncestors($this, $select); }

  /**

• Moves a node to another node when parent changes
  *
  */
  protected function _update()
  {
  if ($this->_cleanData['id_parent'] != $this->id_parent) {

$nodeSize = ($this->_cleanData['rt'] - $this->_cleanData['lt']) + 1;

if ($this->id_parent)

else

// lock tables
$connection = $this->getTable()>getDefaultAdapter()>getConnection();
$connection->exec("LOCK TABLE `".$this->getTable()->info('name')."` WRITE;");

//temporary remove moving node and children
$data = array(
'lt' => new Zend_Db_Expr('0-`lt`'),
'rt' => new Zend_Db_Expr('0-`rt`')
);
$where = '`lt` >= "' . $this->_cleanData['lt'] . '" AND `rt` <= "'. $this->_cleanData['rt'] . '"';
$this->getTable()->update($data,$where);

//step 2: decrease left and/or right position values of currently 'lower' items (and parents)
$data = array(
'lt' => new Zend_Db_Expr('`lt` - ' . $nodeSize)
);
$where = '`lt` > ' . $this->_cleanData['rt'];
$this->getTable()->update($data,$where);

$data = array(
'rt' => new Zend_Db_Expr('`rt` - ' . $nodeSize)
);
$where = '`rt` > ' . $this->_cleanData['rt'];
$this->getTable()->update($data,$where);

//step 3: increase left and/or right position values of future 'lower' items (and parents)
$data = array(
'lt' => new Zend_Db_Expr('`lt` + ' . $nodeSize)
);
$limit = ($maxRt > $this->_cleanData['rt']) ? $maxRt - $nodeSize : $maxRt ;
$where = '`lt` >= ' . $limit;
$this->getTable()->update($data,$where);

$data = array(
'rt' => new Zend_Db_Expr('`rt` + ' . $nodeSize)
);
$limit = ($maxRt > $this->_cleanData['rt']) ? $maxRt - $nodeSize : $maxRt;
$where = '`rt` >= ' . $limit;
$this->getTable()->update($data, $where);

//step 4: move node (and it's subnodes)
$limit1 = ($maxRt > $this->_cleanData['rt']) ? $maxRt - $this->_cleanData['rt'] 1 : $maxRt - $this>_cleanData['rt'] -1 + $nodeSize;
$limit2 = ($maxRt > $this->_cleanData['rt']) ? $maxRt - $this->_cleanData['rt'] 1 : $maxRt - $this>_cleanData['rt'] -1 + $nodeSize;
$data = array(
'lt' => new Zend_Db_Expr('0-(`lt`)+' . $limit1),
'rt' => new Zend_Db_Expr('0-(`rt`)+' . $limit2),
);
$where = '`lt` <= "' . (0-$this->_cleanData['lt']) . '" and `rt` >= "'.(0-$this->_cleanData['rt'] . '"');
$this->getTable()->update($data,$where);

// unlock tables
$connection->exec("UNLOCK TABLES;");
}
}

}

?>
]]></ac:plain-text-body></ac:macro>
<p>I also have delete() proxy in row class to table method.</p>

<p>I prefer NestedSet over MPTT.  </p>

<p>Is there anything that we (the community) can do to help push this proposal along? </p>

<p>I have some free time to help get this going again. Some of the things I want to look at are:</p>

<p><strong>Row deletion</strong><br />
When a leaf is deleted, it's simple to adjust the left/right values so there are no gaps, but when a branch is deleted there must be some mechanism in place to handle the hole. In a previous e-mail conversation with Nick and others, it was suggested to mimic foreign key constraints, so we would have options like:<br />
– Cascade: Deletes all child nodes when a parent node is deleted.<br />
– Restrict: Enforces that no child nodes must exist before deleting the node.<br />
– Reassign/Reattach: Deletes the node and reassigns all children to the original node's parent.<br />
– Set null: Sets all children's parents to the null, effectively moving them to the root of the tree.<br />
Each table instance could define its own delete rule, so that table A could use the "cascade" option while table B uses the "restrict" option.</p>

<p><strong>Auto-rebuild MPTT Data</strong><br />
Set an auto-rebuild option that randomly rebuilds the MPTT data after X number of instantiations. This may be useful for projects where another file is also updating this table but does not provide MPTT data (for example, batch imports).</p>

<p>@michael, I like your implementation of the MPTT Row object. This would be a great addition to the proposal.</p>

<p>Overall my only concern with this project is the SQL itself – is it valid SQL across all major DBs? I know this works in MySQL but we would need to test others and, if necessary, move the SQL to another class.</p>

<p>Any thoughts on moving the SQL to the Zend_Db_Adapter_* classes? That would allow each DB to provide their own MPTT implementation.</p>

<p>Hi, how does it look, any updates? It would be very nice if this component is implemented soon.</p>

<p>Archiving this proposal, feel free to recover it when you want to work on it again. For more details see <a href="http://framework.zend.com/wiki/display/ZFDEV/Archiving+of+abandoned+proposals+(Feb+5+2011)">this email</a>.</p>