protected function getTableIndexes(): array
    {
        $data = [];

        $idxs = $this->db->schema->getTableIndexes($this->tableName, true);

        /* @var $idx IndexConstraint */
        foreach ($idxs as $idx) {
            if (!$idx->isPrimary) {
                $data[$idx->name] = new TableIndex([
                    'name' => $idx->name,
                    'unique' => $idx->isUnique,
                    'columns' => $idx->columnNames
                ]);
            }
        }

        return $data;
    }