< API16:JTableUsergroup
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Method to recursively rebuild the nested set tree.

[Edit Descripton]



rebuild($parent_id=0, $left=0)
Parameter Name Default Value Description
$parent_id 0 The root of the tree to rebuild.
$left 0 The left id to start with in building the tree.


boolean True on success

Defined in



jimport( 'joomla.database.table.usergroup' );

Source Body

function rebuild($parent_id = 0, $left = 0)
        // get the database object
        $db = &$this->_db;
        // get all children of this node
                'SELECT id FROM '. $this->_tbl .
                ' WHERE parent_id='. (int)$parent_id .
                ' ORDER BY parent_id, title'
        $children = $db->loadResultArray();
        // the right value of this node is the left value + 1
        $right = $left + 1;
        // execute this function recursively over all children
        for ($i=0,$n=count($children); $i < $n; $i++)
                // $right is the current right value, which is incremented on recursion return
                $right = $this->rebuild($children[$i], $right);
                // if there is an update failure, return false to break out of the recursion
                if ($right === false) {
                        return false;
        // we've got the left value, and now that we've processed
        // the children of this node we also know the right value
                'UPDATE '. $this->_tbl .
                ' SET lft='. (int)$left .', rgt='. (int)$right .
                ' WHERE id='. (int)$parent_id
        // if there is an update failure, return false to break out of the recursion
        if (!$db->query()) {
                return false;
        // return the right value of this node + 1
        return $right + 1;

[Edit See Also] SeeAlso:JTableUsergroup/rebuild


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