Coverage for python/lsst/daf/butler/registry/queries/expressions/categorize.py: 7%
102 statements
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« prev ^ index » next coverage.py v7.3.1, created at 2023-10-02 08:00 +0000
1# This file is part of daf_butler.
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 software is dual licensed under the GNU General Public License and also
10# under a 3-clause BSD license. Recipients may choose which of these licenses
11# to use; please see the files gpl-3.0.txt and/or bsd_license.txt,
12# respectively. If you choose the GPL option then the following text applies
13# (but note that there is still no warranty even if you opt for BSD instead):
14#
15# This program is free software: you can redistribute it and/or modify
16# it under the terms of the GNU General Public License as published by
17# the Free Software Foundation, either version 3 of the License, or
18# (at your option) any later version.
19#
20# This program is distributed in the hope that it will be useful,
21# but WITHOUT ANY WARRANTY; without even the implied warranty of
22# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23# GNU General Public License for more details.
24#
25# You should have received a copy of the GNU General Public License
26# along with this program. If not, see <http://www.gnu.org/licenses/>.
27from __future__ import annotations
29__all__ = () # all symbols intentionally private; for internal package use.
31import enum
32from typing import cast
34from ....core import Dimension, DimensionElement, DimensionGraph, DimensionUniverse
37class ExpressionConstant(enum.Enum):
38 """Enumeration for constants recognized in all expressions."""
40 NULL = "null"
41 INGEST_DATE = "ingest_date"
44def categorizeConstant(name: str) -> ExpressionConstant | None:
45 """Categorize an identifier in a parsed expression as one of a few global
46 constants.
48 Parameters
49 ----------
50 name : `str`
51 Identifier to categorize. Case-insensitive.
53 Returns
54 -------
55 categorized : `ExpressionConstant` or `None`
56 Enumeration value if the string represents a constant, `None`
57 otherwise.
58 """
59 try:
60 return ExpressionConstant(name.lower())
61 except ValueError:
62 return None
65def categorizeElementId(universe: DimensionUniverse, name: str) -> tuple[DimensionElement, str | None]:
66 """Categorize an identifier in a parsed expression as either a `Dimension`
67 name (indicating the primary key for that dimension) or a non-primary-key
68 column in a `DimensionElement` table.
70 Parameters
71 ----------
72 universe : `DimensionUniverse`
73 All known dimensions.
74 name : `str`
75 Identifier to categorize.
77 Returns
78 -------
79 element : `DimensionElement`
80 The `DimensionElement` the identifier refers to.
81 column : `str` or `None`
82 The name of a column in the table for ``element``, or `None` if
83 ``element`` is a `Dimension` and the requested column is its primary
84 key.
86 Raises
87 ------
88 LookupError
89 Raised if the identifier refers to a nonexistent `DimensionElement`
90 or column.
91 RuntimeError
92 Raised if the expression refers to a primary key in an illegal way.
93 This exception includes a suggestion for how to rewrite the expression,
94 so at least its message should generally be propagated up to a context
95 where the error can be interpreted by a human.
96 """
97 table, _, column = name.partition(".")
98 if column:
99 try:
100 element = universe[table]
101 except KeyError:
102 if table == "timespan" or table == "datetime" or table == "timestamp":
103 raise LookupError(
104 "Dimension element name cannot be inferred in this context; "
105 f"use <dimension>.timespan.{column} instead."
106 ) from None
107 raise LookupError(f"No dimension element with name {table!r} in {name!r}.") from None
108 if isinstance(element, Dimension) and column == element.primaryKey.name:
109 # Allow e.g. "visit.id = x" instead of just "visit = x"; this
110 # can be clearer.
111 return element, None
112 elif column in element.graph.names:
113 # User said something like "patch.tract = x" or
114 # "tract.tract = x" instead of just "tract = x" or
115 # "tract.id = x", which is at least needlessly confusing and
116 # possibly not actually a column name, though we can guess
117 # what they were trying to do.
118 # Encourage them to clean that up and try again.
119 name = universe[column].primaryKey.name # type: ignore
120 raise RuntimeError(
121 f"Invalid reference to '{table}.{column}' "
122 f"in expression; please use '{column}' or "
123 f"'{column}.{name}' instead."
124 )
125 else:
126 return element, column
127 else:
128 try:
129 dimension = universe[table]
130 except KeyError as err:
131 raise LookupError(f"No dimension with name '{table}'.") from err
132 return dimension, None
135def categorizeOrderByName(graph: DimensionGraph, name: str) -> tuple[DimensionElement, str | None]:
136 """Categorize an identifier in an ORDER BY clause.
138 Parameters
139 ----------
140 graph : `DimensionGraph`
141 All known dimensions.
142 name : `str`
143 Identifier to categorize.
145 Returns
146 -------
147 element : `DimensionElement`
148 The `DimensionElement` the identifier refers to.
149 column : `str` or `None`
150 The name of a column in the table for ``element``, or `None` if
151 ``element`` is a `Dimension` and the requested column is its primary
152 key.
154 Raises
155 ------
156 ValueError
157 Raised if element name is not found in a graph, metadata name is not
158 recognized, or if there is more than one element has specified
159 metadata.
161 Notes
162 -----
163 For ORDER BY identifiers we use slightly different set of rules compared to
164 the rules in `categorizeElementId`:
166 - Name can be a dimension element name. e.g. ``visit``.
167 - Name can be an element name and a metadata name (or key name) separated
168 by dot, e.g. ``detector.full_name``.
169 - Name can be a metadata name without element name prefix, e.g.
170 ``day_obs``; in that case metadata (or key) is searched in all elements
171 present in a graph. Exception is raised if name appears in more than one
172 element.
173 - Two special identifiers ``timespan.begin`` and ``timespan.end`` can be
174 used with temporal elements, if element name is not given then a temporal
175 element from a graph is used.
176 """
177 element: DimensionElement
178 field_name: str | None = None
179 if name in ("timespan.begin", "timespan.end"):
180 matches = [element for element in graph.elements if element.temporal]
181 if len(matches) == 1:
182 element = matches[0]
183 field_name = name
184 elif len(matches) > 1:
185 raise ValueError(
186 "Timespan exists in more than one dimension element "
187 f"({', '.join(element.name for element in matches)}); "
188 "qualify timespan with specific dimension name."
189 )
190 else:
191 raise ValueError(f"Cannot find any temporal dimension element for '{name}'.")
192 elif "." not in name:
193 # No dot, can be either a dimension name or a field name (in any of
194 # the known elements)
195 if name in graph.elements.names:
196 element = graph.elements[name]
197 else:
198 # Can be a metadata name or any of unique keys
199 match_pairs: list[tuple[DimensionElement, bool]] = [
200 (elem, False) for elem in graph.elements if name in elem.metadata.names
201 ]
202 match_pairs += [(dim, True) for dim in graph if name in dim.uniqueKeys.names]
203 if len(match_pairs) == 1:
204 element, is_dimension_key = match_pairs[0]
205 if is_dimension_key and name == cast(Dimension, element).primaryKey.name:
206 # Need to treat reference to primary key field as a
207 # reference to the dimension name.
208 return element, None
209 field_name = name
210 elif len(match_pairs) > 1:
211 raise ValueError(
212 f"Metadata '{name}' exists in more than one dimension element "
213 f"({', '.join(element.name for element, _ in match_pairs)}); "
214 "qualify field name with dimension name."
215 )
216 else:
217 raise ValueError(f"Metadata '{name}' cannot be found in any dimension.")
218 else:
219 # qualified name, must be a dimension element and a field
220 elem_name, _, field_name = name.partition(".")
221 if elem_name not in graph.elements.names:
222 if field_name == "begin" or field_name == "end":
223 raise ValueError(
224 f"Unknown dimension element {elem_name!r}; perhaps you meant 'timespan.{field_name}'?"
225 )
226 raise ValueError(f"Unknown dimension element {elem_name!r}.")
227 element = graph.elements[elem_name]
228 if field_name in ("timespan.begin", "timespan.end"):
229 if not element.temporal:
230 raise ValueError(f"Cannot use '{field_name}' with non-temporal element '{element}'.")
231 elif isinstance(element, Dimension) and field_name == element.primaryKey.name:
232 # Primary key is optional
233 field_name = None
234 else:
235 if not (
236 field_name in element.metadata.names
237 or (isinstance(element, Dimension) and field_name in element.alternateKeys.names)
238 ):
239 raise ValueError(f"Field '{field_name}' does not exist in '{element}'.")
241 return element, field_name
244def categorizeElementOrderByName(element: DimensionElement, name: str) -> str | None:
245 """Categorize an identifier in an ORDER BY clause for a single element.
247 Parameters
248 ----------
249 element : `DimensionElement`
250 Dimension element.
251 name : `str`
252 Identifier to categorize.
254 Returns
255 -------
256 column : `str` or `None`
257 The name of a column in the table for ``element``, or `None` if
258 ``element`` is a `Dimension` and the requested column is its primary
259 key.
261 Raises
262 ------
263 ValueError
264 Raised if name is not recognized.
266 Notes
267 -----
268 For ORDER BY identifiers we use slightly different set of rules compared to
269 the rules in `categorizeElementId`:
271 - Name can be a dimension element name. e.g. ``visit``.
272 - Name can be an element name and a metadata name (or key name) separated
273 by dot, e.g. ``detector.full_name``, element name must correspond to
274 ``element`` argument
275 - Name can be a metadata name without element name prefix, e.g.
276 ``day_obs``.
277 - Two special identifiers ``timespan.begin`` and ``timespan.end`` can be
278 used with temporal elements.
279 """
280 field_name: str | None = None
281 if name in ("timespan.begin", "timespan.end"):
282 if element.temporal:
283 field_name = name
284 else:
285 raise ValueError(f"Cannot use '{field_name}' with non-temporal element '{element}'.")
286 elif "." not in name:
287 # No dot, can be either a dimension name or a field name (in any of
288 # the known elements)
289 if name == element.name:
290 # Must be a dimension element
291 if not isinstance(element, Dimension):
292 raise ValueError(f"Element '{element}' is not a dimension.")
293 else:
294 # Can be a metadata name or any of the keys, but primary key needs
295 # to be treated the same as a reference to the dimension name
296 # itself.
297 if isinstance(element, Dimension):
298 if name == element.primaryKey.name:
299 return None
300 elif name in element.uniqueKeys.names:
301 return name
302 if name in element.metadata.names:
303 return name
304 raise ValueError(f"Field '{name}' does not exist in '{element}'.")
305 else:
306 # qualified name, must be a dimension element and a field
307 elem_name, _, field_name = name.partition(".")
308 if elem_name != element.name:
309 if field_name == "begin" or field_name == "end":
310 extra = f"; perhaps you meant 'timespan.{field_name}'?"
311 else:
312 extra = "."
313 raise ValueError(f"Element name mismatch: '{elem_name}' instead of '{element}'{extra}")
314 if field_name in ("timespan.begin", "timespan.end"):
315 if not element.temporal:
316 raise ValueError(f"Cannot use '{field_name}' with non-temporal element '{element}'.")
317 elif isinstance(element, Dimension) and field_name == element.primaryKey.name:
318 # Primary key is optional
319 field_name = None
320 else:
321 if not (
322 field_name in element.metadata.names
323 or (isinstance(element, Dimension) and field_name in element.alternateKeys.names)
324 ):
325 raise ValueError(f"Field '{field_name}' does not exist in '{element}'.")
327 return field_name