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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 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/>. 

21from __future__ import annotations 

22 

23__all__ = ["QuerySummary", "RegistryManagers"] # other classes here are local to subpackage 

24 

25from dataclasses import dataclass 

26from typing import Iterator, List, Optional, Union 

27 

28from sqlalchemy.sql import ColumnElement 

29 

30from lsst.sphgeom import Region 

31from ...core import ( 

32 TimespanDatabaseRepresentation, 

33 DataCoordinate, 

34 DatasetType, 

35 Dimension, 

36 DimensionElement, 

37 DimensionGraph, 

38 DimensionUniverse, 

39 NamedKeyDict, 

40 NamedValueSet, 

41 SkyPixDimension, 

42) 

43from ..interfaces import ( 

44 CollectionManager, 

45 DatasetRecordStorageManager, 

46 DimensionRecordStorageManager, 

47) 

48# We're not trying to add typing to the lex/yacc parser code, so MyPy 

49# doesn't know about some of these imports. 

50from .exprParser import Node, ParserYacc # type: ignore 

51 

52 

53@dataclass 

54class QueryWhereExpression: 

55 """A struct representing a parsed user-provided WHERE expression. 

56 

57 Parameters 

58 ---------- 

59 universe : `DimensionUniverse` 

60 All known dimensions. 

61 expression : `str`, optional 

62 The string expression to parse. 

63 """ 

64 def __init__(self, universe: DimensionUniverse, expression: Optional[str] = None): 

65 if expression: 

66 from .expressions import InspectionVisitor 

67 try: 

68 parser = ParserYacc() 

69 self.tree = parser.parse(expression) 

70 except Exception as exc: 

71 raise RuntimeError(f"Failed to parse user expression `{expression}'.") from exc 

72 visitor = InspectionVisitor(universe) 

73 assert self.tree is not None 

74 self.tree.visit(visitor) 

75 self.keys = visitor.keys 

76 self.metadata = visitor.metadata 

77 else: 

78 self.tree = None 

79 self.keys = NamedValueSet() 

80 self.metadata = NamedKeyDict() 

81 

82 tree: Optional[Node] 

83 """The parsed user expression tree, if present (`Node` or `None`). 

84 """ 

85 

86 keys: NamedValueSet[Dimension] 

87 """All dimensions whose keys are referenced by the expression 

88 (`NamedValueSet` of `Dimension`). 

89 """ 

90 

91 metadata: NamedKeyDict[DimensionElement, List[str]] 

92 """All dimension elements metadata fields referenced by the expression 

93 (`NamedKeyDict` mapping `DimensionElement` to a `set` of field names). 

94 """ 

95 

96 

97@dataclass 

98class QuerySummary: 

99 """A struct that holds and categorizes the dimensions involved in a query. 

100 

101 A `QuerySummary` instance is necessary to construct a `QueryBuilder`, and 

102 it needs to include all of the dimensions that will be included in the 

103 query (including any needed for querying datasets). 

104 

105 Parameters 

106 ---------- 

107 requested : `DimensionGraph` 

108 The dimensions whose primary keys should be included in the result rows 

109 of the query. 

110 dataId : `DataCoordinate`, optional 

111 A fully-expanded data ID identifying dimensions known in advance. If 

112 not provided, will be set to an empty data ID. ``dataId.hasRecords()`` 

113 must return `True`. 

114 expression : `str` or `QueryWhereExpression`, optional 

115 A user-provided string WHERE expression. 

116 whereRegion : `lsst.sphgeom.Region`, optional 

117 A spatial region that all rows must overlap. If `None` and ``dataId`` 

118 is not `None`, ``dataId.region`` will be used. 

119 """ 

120 def __init__(self, requested: DimensionGraph, *, 

121 dataId: Optional[DataCoordinate] = None, 

122 expression: Optional[Union[str, QueryWhereExpression]] = None, 

123 whereRegion: Optional[Region] = None): 

124 self.requested = requested 

125 self.dataId = dataId if dataId is not None else DataCoordinate.makeEmpty(requested.universe) 

126 self.expression = (expression if isinstance(expression, QueryWhereExpression) 

127 else QueryWhereExpression(requested.universe, expression)) 

128 if whereRegion is None and self.dataId is not None: 

129 whereRegion = self.dataId.region 

130 self.whereRegion = whereRegion 

131 

132 requested: DimensionGraph 

133 """Dimensions whose primary keys should be included in the result rows of 

134 the query (`DimensionGraph`). 

135 """ 

136 

137 dataId: DataCoordinate 

138 """A data ID identifying dimensions known before query construction 

139 (`DataCoordinate`). 

140 

141 ``dataId.hasRecords()`` is guaranteed to return `True`. 

142 """ 

143 

144 whereRegion: Optional[Region] 

145 """A spatial region that all result rows must overlap 

146 (`lsst.sphgeom.Region` or `None`). 

147 """ 

148 

149 expression: QueryWhereExpression 

150 """Information about any parsed user WHERE expression 

151 (`QueryWhereExpression`). 

152 """ 

153 

154 @property 

155 def universe(self) -> DimensionUniverse: 

156 """All known dimensions (`DimensionUniverse`). 

157 """ 

158 return self.requested.universe 

159 

160 @property 

161 def spatial(self) -> NamedValueSet[DimensionElement]: 

162 """Dimension elements whose regions and skypix IDs should be included 

163 in the query (`NamedValueSet` of `DimensionElement`). 

164 """ 

165 # An element may participate spatially in the query if: 

166 # - it's the most precise spatial element for its system in the 

167 # requested dimensions (i.e. in `self.requested.spatial`); 

168 # - it isn't also given at query construction time. 

169 result: NamedValueSet[DimensionElement] = NamedValueSet() 

170 for family in self.mustHaveKeysJoined.spatial: 

171 element = family.choose(self.mustHaveKeysJoined.elements) 

172 assert isinstance(element, DimensionElement) 

173 if element not in self.dataId.graph.elements: 

174 result.add(element) 

175 if len(result) == 1: 

176 # There's no spatial join, but there might be a WHERE filter based 

177 # on a given region. 

178 if self.dataId.graph.spatial: 

179 # We can only perform those filters against SkyPix dimensions, 

180 # so if what we have isn't one, add the common SkyPix dimension 

181 # to the query; the element we have will be joined to that. 

182 element, = result 

183 if not isinstance(element, SkyPixDimension): 

184 result.add(self.universe.commonSkyPix) 

185 else: 

186 # There is no spatial join or filter in this query. Even 

187 # if this element might be associated with spatial 

188 # information, we don't need it for this query. 

189 return NamedValueSet() 

190 elif len(result) > 1: 

191 # There's a spatial join. Those require the common SkyPix 

192 # system to be included in the query in order to connect them. 

193 result.add(self.universe.commonSkyPix) 

194 return result 

195 

196 @property 

197 def temporal(self) -> NamedValueSet[DimensionElement]: 

198 """Dimension elements whose timespans should be included in the 

199 query (`NamedValueSet` of `DimensionElement`). 

200 """ 

201 # An element may participate temporally in the query if: 

202 # - it's the most precise temporal element for its system in the 

203 # requested dimensions (i.e. in `self.requested.temporal`); 

204 # - it isn't also given at query construction time. 

205 result: NamedValueSet[DimensionElement] = NamedValueSet() 

206 for family in self.mustHaveKeysJoined.temporal: 

207 element = family.choose(self.mustHaveKeysJoined.elements) 

208 assert isinstance(element, DimensionElement) 

209 if element not in self.dataId.graph.elements: 

210 result.add(element) 

211 if len(result) == 1 and not self.dataId.graph.temporal: 

212 # No temporal join or filter. Even if this element might be 

213 # associated with temporal information, we don't need it for this 

214 # query. 

215 return NamedValueSet() 

216 return result 

217 

218 @property 

219 def mustHaveKeysJoined(self) -> DimensionGraph: 

220 """Dimensions whose primary keys must be used in the JOIN ON clauses 

221 of the query, even if their tables do not appear (`DimensionGraph`). 

222 

223 A `Dimension` primary key can appear in a join clause without its table 

224 via a foreign key column in table of a dependent dimension element or 

225 dataset. 

226 """ 

227 names = set(self.requested.names | self.expression.keys.names) 

228 return DimensionGraph(self.universe, names=names) 

229 

230 @property 

231 def mustHaveTableJoined(self) -> NamedValueSet[DimensionElement]: 

232 """Dimension elements whose associated tables must appear in the 

233 query's FROM clause (`NamedValueSet` of `DimensionElement`). 

234 """ 

235 result = NamedValueSet(self.spatial | self.temporal | self.expression.metadata.keys()) 

236 for dimension in self.mustHaveKeysJoined: 

237 if dimension.implied: 

238 result.add(dimension) 

239 for element in self.mustHaveKeysJoined.union(self.dataId.graph).elements: 

240 if element.alwaysJoin: 

241 result.add(element) 

242 return result 

243 

244 

245@dataclass 

246class DatasetQueryColumns: 

247 """A struct containing the columns used to reconstruct `DatasetRef` 

248 instances from query results. 

249 """ 

250 

251 datasetType: DatasetType 

252 """The dataset type being queried (`DatasetType`). 

253 """ 

254 

255 id: ColumnElement 

256 """Column containing the unique integer ID for this dataset. 

257 """ 

258 

259 runKey: ColumnElement 

260 """Foreign key column to the `~CollectionType.RUN` collection that holds 

261 this dataset. 

262 """ 

263 

264 def __iter__(self) -> Iterator[ColumnElement]: 

265 yield self.id 

266 yield self.runKey 

267 

268 

269@dataclass 

270class QueryColumns: 

271 """A struct organizing the columns in an under-construction or currently- 

272 executing query. 

273 

274 Takes no parameters at construction, as expected usage is to add elements 

275 to its container attributes incrementally. 

276 """ 

277 def __init__(self) -> None: 

278 self.keys = NamedKeyDict() 

279 self.timespans = NamedKeyDict() 

280 self.regions = NamedKeyDict() 

281 self.datasets = None 

282 

283 keys: NamedKeyDict[Dimension, List[ColumnElement]] 

284 """Columns that correspond to the primary key values of dimensions 

285 (`NamedKeyDict` mapping `Dimension` to a `list` of `ColumnElement`). 

286 

287 Each value list contains columns from multiple tables corresponding to the 

288 same dimension, and the query should constrain the values of those columns 

289 to be the same. 

290 

291 In a `Query`, the keys of this dictionary must include at least the 

292 dimensions in `QuerySummary.requested` and `QuerySummary.dataId.graph`. 

293 """ 

294 

295 timespans: NamedKeyDict[DimensionElement, TimespanDatabaseRepresentation] 

296 """Columns that correspond to timespans for elements that participate in a 

297 temporal join or filter in the query (`NamedKeyDict` mapping 

298 `DimensionElement` to `TimespanDatabaseRepresentation`). 

299 

300 In a `Query`, the keys of this dictionary must be exactly the elements 

301 in `QuerySummary.temporal`. 

302 """ 

303 

304 regions: NamedKeyDict[DimensionElement, ColumnElement] 

305 """Columns that correspond to regions for elements that participate in a 

306 spatial join or filter in the query (`NamedKeyDict` mapping 

307 `DimensionElement` to `ColumnElement`). 

308 

309 In a `Query`, the keys of this dictionary must be exactly the elements 

310 in `QuerySummary.spatial`. 

311 """ 

312 

313 datasets: Optional[DatasetQueryColumns] 

314 """Columns that can be used to construct `DatasetRef` instances from query 

315 results. 

316 (`DatasetQueryColumns` or `None`). 

317 """ 

318 

319 def isEmpty(self) -> bool: 

320 """Return `True` if this query has no columns at all. 

321 """ 

322 return not (self.keys or self.timespans or self.regions or self.datasets is not None) 

323 

324 def getKeyColumn(self, dimension: Union[Dimension, str]) -> ColumnElement: 

325 """ Return one of the columns in self.keys for the given dimension. 

326 

327 The column selected is an implentation detail but is guaranteed to 

328 be deterministic and consistent across multiple calls. 

329 

330 Parameters 

331 ---------- 

332 dimension : `Dimension` or `str` 

333 Dimension for which to obtain a key column. 

334 

335 Returns 

336 ------- 

337 column : `sqlalchemy.sql.ColumnElement` 

338 SQLAlchemy column object. 

339 """ 

340 # Choosing the last element here is entirely for human readers of the 

341 # query (e.g. developers debugging things); it makes it more likely a 

342 # dimension key will be provided by the dimension's own table, or 

343 # failing that, some closely related dimension, which might be less 

344 # surprising to see than e.g. some dataset subquery. From the 

345 # database's perspective this is entirely arbitrary, because the query 

346 # guarantees they all have equal values. 

347 return self.keys[dimension][-1] 

348 

349 

350@dataclass 

351class RegistryManagers: 

352 """Struct used to pass around the manager objects that back a `Registry` 

353 and are used internally by the query system. 

354 """ 

355 

356 collections: CollectionManager 

357 """Manager for collections (`CollectionManager`). 

358 """ 

359 

360 datasets: DatasetRecordStorageManager 

361 """Manager for datasets and dataset types (`DatasetRecordStorageManager`). 

362 """ 

363 

364 dimensions: DimensionRecordStorageManager 

365 """Manager for dimensions (`DimensionRecordStorageManager`). 

366 """