/**
* Converts parsed field expression $formula into SQL column expression. If needed, introduces new joins in current
* SELECT.
*
* @param Mana_Db_Model_Formula_Context $context
* @param Mana_Db_Model_Formula_Node_Field $formula
* @param int $index
* @throws Mana_Db_Exception_Formula
* @return Mana_Db_Model_Formula_Expr
*/
protected function _selectFieldRecursively($context, $formula, $index)
{
$processor = $context->getProcessor();
if (isset($formula->identifiers[$index])) {
$identifier = $formula->identifiers[$index];
} else {
throw new Mana_Db_Exception_Formula(Mage::helper('mana_db')->__("'%s' is entity, but field expected", implode('.', $formula->identifiers)));
}
if ($result = $processor->selectField($context, implode('.', array_slice($formula->identifiers, $index)))) {
$context->getEntityHelper()->selectField($context, $formula, $result);
return $result;
} else {
if ($entity = $processor->selectEntity($context, $identifier)) {
$entity->getHelper()->select($context, $entity);
$result = $this->_selectFieldRecursively($context, $formula, ++$index);
$entity->getHelper()->endSelect($context, $entity);
return $result;
} elseif ($index == 0) {
$context->setEntity($context->getPrimaryEntity());
return $this->_selectFieldRecursively($context, $formula, $index);
} else {
throw new Mana_Db_Exception_Formula($this->__("Unknown field or entity '%s'", $identifier));
}
}
}
