/**
* Constructor
*
* @param {DB} $db Handle to database
* @param {string} $id ID of parent query - $id should refer to an atomic query
* @param {string} $terms Query terms corresponding to the child queries of the tree
*/
public function __construct(&$db, $id, $terms = array())
{
parent::__construct($db);
// Create the root query
$this->base = $this->db->query($id);
// Ensure root query fields are copied to this query
$this->update();
// Check for child aliases
$aliases = array();
foreach ($this->output->fields as $field => $spec) {
if (property_exists($spec, 'child') && $spec->child != $field) {
$aliases[$field] = $spec->child;
}
}
$terms = Term::convertAliases($terms, $aliases);
// Add root or id as filter to each child
$linkID = $this->prefix();
if (!$linkID) {
throw new \Exception("Query '{$id}' has no prefix");
}
for ($i = 0; $i < count($terms); $i++) {
$terms[$i] = "(" . $terms[$i] . "):" . $linkID;
}
// Create a child query for each term
$this->linkList($terms, false);
}
