protected function _columnsForRelation(DbRelation $relation, PDOConnection $connection, $relationName)
{
$sqlColumns = $connection->getTableColumns($relation->getTableName());
$columnAlias = str_replace('.', '_', str_replace('_', '__', $relationName));
$columns = [];
foreach ($sqlColumns as $column) {
$columns[] = "`{$relation->getTableAlias()}`.`{$column['Field']}` as ___{$columnAlias}___{$column['Field']}";
}
return $columns;
}
