@staticmethod
def _get_index_keys(formatted_columns):
    """Get columns that are index key"""
    index_keys = list()
    for column in formatted_columns:
        column_name = column[0]
        column_is_primary_key = column[3]
        if not column_is_primary_key and column_name.lower().find('id', 0, 2
            ) != -1:
            index_keys.append(column_name)
    return index_keys
