Coverage for python/lsst/daf/relation/_columns/_tag.py: 82%

11 statements  

« prev     ^ index     » next       coverage.py v6.5.0, created at 2023-01-10 10:30 +0000

1# This file is part of daf_relation. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (http://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This program is free software: you can redistribute it and/or modify 

10# it under the terms of the GNU General Public License as published by 

11# the Free Software Foundation, either version 3 of the License, or 

12# (at your option) any later version. 

13# 

14# This program is distributed in the hope that it will be useful, 

15# but WITHOUT ANY WARRANTY; without even the implied warranty of 

16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

17# GNU General Public License for more details. 

18# 

19# You should have received a copy of the GNU General Public License 

20# along with this program. If not, see <http://www.gnu.org/licenses/>. 

21 

22from __future__ import annotations 

23 

24__all__ = ("ColumnTag",) 

25 

26from collections.abc import Hashable 

27from typing import Protocol 

28 

29 

30class ColumnTag(Hashable, Protocol): 

31 """An interface for objects that represent columns in a relation. 

32 

33 See :ref:`lsst.daf.relation-overview-column_tags` for details. 

34 """ 

35 

36 @property 

37 def qualified_name(self) -> str: 

38 """A string that is just as unique as this `ColumnTag` is, for use in 

39 engines that require a string for column names (`str`). 

40 

41 This does not need to be limited to avoid special characters; we assume 

42 it can and will be appropriately quoted when necessary. 

43 """ 

44 ... 

45 

46 @property 

47 def is_key(self) -> bool: 

48 """Whether this column can be used for deduplication and join 

49 equality-constraints (`bool`). 

50 

51 Columns that are not keys are assumed to always be accompanied in 

52 relations by related key columns that should be used instead. 

53 """ 

54 ...