def add_primary_key_ddl(table, sorted_in_comment, lines_ct, lines_sc):
	"""adds information about primary key columns"""
	rs = select_qry(TPRIMARY_KEYS_INFO_SQL % (table))
	pk_columns = []
	for row in rs:
		pk_columns.append(row[0].lower())
	if pk_columns:
		tmp_str = 'PRIMARY KEY (%s)' % (', '.join(pk_columns))
		lines_ct.append(tmp_str)
		if sorted_in_comment:
			lines_sc.append(tmp_str)
	return pk_columns
adds information about primary key columns
recipes/Python/576534_Dump_Oracle_db_schema_to_text/recipe-576534.py