Mercurial > pylearn
annotate pylearn/dbdict/api0.py @ 621:7041749cf804
untested changes to close sessions in api0
| author | James Bergstra <bergstrj@iro.umontreal.ca> |
|---|---|
| date | Sun, 18 Jan 2009 21:14:14 -0500 |
| parents | fa6585609e01 |
| children | d2d582bcf7dc |
| rev | line source |
|---|---|
| 538 | 1 from sqlalchemy import create_engine, desc |
|
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2 import sqlalchemy.pool |
| 538 | 3 from sqlalchemy.orm import sessionmaker |
| 4 from sqlalchemy import Table, Column, MetaData, ForeignKey | |
| 5 from sqlalchemy import Integer, String, Float, Boolean, DateTime, Text, Binary | |
| 6 from sqlalchemy.orm import mapper, relation, backref, eagerload | |
| 7 from sqlalchemy.sql import operators, select | |
| 8 from sql_commands import crazy_sql_command | |
| 9 | |
| 10 class Todo(Exception): """Replace this with some working code!""" | |
| 11 | |
| 12 class DbHandle (object): | |
| 13 """ | |
| 14 This class also provides filtering shortcuts that hide the names of the | |
| 15 DbHandle internal databases. | |
| 16 | |
| 17 Attributes: | |
| 18 dict_table | |
| 19 pair_table | |
| 20 link_table | |
| 21 | |
| 22 | |
| 23 | |
| 24 dict_table | |
| 25 | |
| 26 An SqlAlchemy-mapped class corresponding to database table with the | |
| 27 following schema: | |
| 28 | |
| 29 Column('id', Integer, primary_key=True) | |
| 30 Column('create', DateTime) | |
| 31 Column('write', DateTime) | |
| 32 Column('read', DateTime) | |
| 33 | |
| 34 #TODO: reconsider create/read/write | |
| 35 | |
| 36 pair_table | |
| 37 | |
| 38 An SqlAlchemy-mapped class corresponding to database table with the | |
| 39 following schema: | |
| 40 | |
| 41 Column('id', Integer, primary_key=True) | |
| 42 Column('name', String(128)) | |
| 43 Column('ntype', Boolean) | |
| 44 Column('fval', Double) | |
| 45 Column('sval', Text)) | |
| 46 Column('bval', Blob) | |
| 47 | |
| 48 #TODO: Consider difference between text and binary | |
| 49 #TODO: Consider adding a 'type' column | |
| 50 #TODO: Consider union? | |
| 51 #TODO: Are there stanard ways of doing this kind of thing? | |
| 52 | |
| 53 link_table | |
| 54 | |
| 55 An SqlAlchemy-mapped class corresponding to database table with the | |
| 56 following schema: | |
| 57 | |
| 58 Column('dict_id', Integer, ForeignKey('%s.id' % t_trial), primary_key=True), | |
| 59 Column('keyval_id', Integer, ForeignKey('%s.id' % t_keyval), primary_key=True)) | |
| 60 | |
| 61 """ | |
| 62 | |
| 63 e_bad_table = 'incompatible columns in table' | |
| 64 | |
| 65 def __init__(h_self, Session, engine, dict_table, pair_table, link_table): | |
| 66 h_self._engine = engine; | |
| 67 h_self._dict_table = dict_table | |
| 68 h_self._pair_table = pair_table | |
| 69 h_self._link_table = link_table | |
| 70 | |
| 71 #TODO: replace this crude algorithm (ticket #17) | |
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72 if ['id', 'create', 'write', 'read', 'status', 'priority'] != [c.name for c in dict_table.c]: |
| 538 | 73 raise ValueError(h_self.e_bad_table, dict_table) |
| 74 if ['id', 'name', 'ntype', 'fval', 'sval', 'bval'] != [c.name for c in pair_table.c]: | |
| 75 raise ValueError(h_self.e_bad_table, pair_table) | |
| 76 if ['dict_id', 'pair_id'] != [c.name for c in link_table.c]: | |
| 77 raise ValueError(h_self.e_bad_table, pair_table) | |
| 78 | |
| 79 h_self._session_fn = Session | |
| 80 | |
| 81 class KeyVal (object): | |
| 82 """KeyVal interfaces between python types and the database. | |
| 83 | |
| 84 It encapsulates heuristics for type conversion. | |
| 85 """ | |
| 86 def __init__(k_self, name, val): | |
| 87 k_self.name = name | |
| 88 k_self.val = val | |
| 89 def __repr__(k_self): | |
| 90 return "<Param(%s,'%s', %s)>" % (k_self.id, k_self.name, repr(k_self.val)) | |
| 91 def __get_val(k_self): | |
| 92 val = None | |
| 93 if k_self.fval is not None: val = [int, float][k_self.ntype](k_self.fval) | |
| 94 if k_self.bval is not None: val = eval(str(k_self.bval)) | |
| 95 if k_self.sval is not None: val = k_self.sval | |
| 96 return val | |
| 97 def __set_val(k_self, val): | |
| 98 if isinstance(val, (str,unicode)): | |
| 99 k_self.fval = None | |
| 100 k_self.bval = None | |
| 101 k_self.sval = val | |
| 102 else: | |
| 103 k_self.sval = None | |
| 104 try: | |
| 105 f = float(val) | |
| 106 except (TypeError, ValueError): | |
| 107 f = None | |
| 108 if f is None: #binary data | |
| 109 k_self.bval = repr(val) | |
| 110 assert eval(k_self.bval) == val | |
| 111 k_self.fval = None | |
| 112 k_self.ntype = None | |
| 113 else: | |
| 114 k_self.bval = None | |
| 115 k_self.fval = f | |
| 116 k_self.ntype = isinstance(val,float) | |
| 117 val = property(__get_val, __set_val) | |
| 118 | |
| 119 mapper(KeyVal, pair_table) | |
| 120 | |
| 121 class Dict (object): | |
| 122 """ | |
| 123 Instances are dict-like objects with additional features for | |
| 124 communicating with an active database. | |
| 125 | |
| 126 This class will be mapped by SqlAlchemy to the dict_table. | |
| 127 | |
| 128 Attributes: | |
| 129 handle - reference to L{DbHandle} (creator) | |
| 130 | |
| 131 """ | |
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132 def __init__(d_self, session=None): |
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133 if session is None: |
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134 s = h_self._session_fn() |
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135 s.add(d_self) #d_self transient -> pending |
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136 s.commit() #d_self -> persistent |
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137 s.close() #d_self -> detached |
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138 else: |
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139 s = session |
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140 s.save(d_self) |
| 538 | 141 |
| 142 _forbidden_keys = set(['session']) | |
| 143 | |
| 144 # | |
| 145 # dictionary interface | |
| 146 # | |
| 147 | |
| 148 def __contains__(d_self, key): | |
| 149 for a in d_self._attrs: | |
| 150 if a.name == key: | |
| 151 return True | |
| 152 return False | |
| 153 | |
| 154 def __eq__(self, other): | |
| 155 return dict(self) == dict(other) | |
| 156 def __neq__(self, other): | |
| 157 return dict(self) != dict(other) | |
| 158 | |
| 159 def __getitem__(d_self, key): | |
| 160 for a in d_self._attrs: | |
| 161 if a.name == key: | |
| 162 return a.val | |
| 163 raise KeyError(key) | |
| 164 | |
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165 def __setitem__(d_self, key, val, session=None): |
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166 if session is None: |
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167 s = h_self._session_fn() |
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168 s.add(d_self) |
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169 d_self._set_in_session(key, val, s) |
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170 s.commit() |
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171 s.close() |
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172 else: |
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173 s = session |
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174 s.add(d_self) |
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175 d_self._set_in_session(key, val, s) |
| 538 | 176 |
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177 def __delitem__(d_self, key, session=None): |
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178 if session is None: |
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179 s = h_self._session_fn() |
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180 commit_close = True |
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181 else: |
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182 s = session |
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183 commit_close = False |
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184 s.add(d_self) |
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185 |
| 538 | 186 #find the item to delete in d_self._attrs |
| 187 to_del = None | |
| 188 for i,a in enumerate(d_self._attrs): | |
| 189 if a.name == key: | |
| 190 assert to_del is None | |
| 191 to_del = (i,a) | |
| 192 if to_del is None: | |
| 193 raise KeyError(key) | |
| 194 else: | |
| 195 i, a = to_del | |
| 196 s.delete(a) | |
| 197 del d_self._attrs[i] | |
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198 if commit_close: |
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199 s.commit() |
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200 #s.add(d_self) #why is this here? maybe it should go earlier?? |
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201 s.close() |
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202 else: |
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203 pass |
| 538 | 204 |
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205 def iteritems(d_self): |
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206 return d_self.items() |
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207 |
| 538 | 208 def items(d_self): |
| 209 return [(kv.name, kv.val) for kv in d_self._attrs] | |
| 210 | |
| 211 def keys(d_self): | |
| 212 return [kv.name for kv in d_self._attrs] | |
| 213 | |
| 214 def values(d_self): | |
| 215 return [kv.val for kv in d_self._attrs] | |
| 216 | |
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217 def update(d_self, dct, session=None, **kwargs): |
| 538 | 218 """Like dict.update(), set keys from kwargs""" |
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219 if session is None: |
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220 s = h_self._session_fn() |
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221 commit_close = True |
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222 else: |
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223 s = session |
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224 commit_close = False |
| 538 | 225 for k, v in dct.items(): |
| 226 d_self._set_in_session(k, v, s) | |
| 227 for k, v in kwargs.items(): | |
| 228 d_self._set_in_session(k, v, s) | |
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229 |
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230 if commit_close: |
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231 s.commit() |
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232 s.close() |
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233 else: |
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234 s.add(d_self) #why is this here? maybe it should go earlier?? |
| 538 | 235 |
| 236 def get(d_self, key, default): | |
| 237 try: | |
| 238 return d_self[key] | |
| 239 except KeyError: | |
| 240 return default | |
| 241 | |
| 589 | 242 def __str__(self): |
| 243 return 'Dict'+ str(dict(self)) | |
| 244 | |
| 538 | 245 # |
| 246 # database stuff | |
| 247 # | |
| 248 | |
| 249 def refresh(d_self, session=None): | |
| 250 """Sync key-value pairs from database to self | |
| 251 | |
| 252 @param session: use the given session, and do not commit. | |
| 253 | |
| 254 """ | |
| 255 if session is None: | |
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256 session = h_self._session_fn() |
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257 session.add(d_self) #so session knows about us |
| 538 | 258 session.refresh(d_self) |
| 259 session.commit() | |
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260 session.close() |
| 538 | 261 else: |
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262 session.add(d_self) #so session knows about us |
| 538 | 263 session.refresh(self.dbrow) |
| 264 | |
| 265 def delete(d_self, session=None): | |
| 266 """Delete this dictionary from the database | |
| 267 | |
| 268 @param session: use the given session, and do not commit. | |
| 269 """ | |
| 270 if session is None: | |
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271 session = h_self._session_fn() |
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272 session.add(d_self) #so session knows about us |
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273 session.delete(d_self) #mark for deletion |
| 538 | 274 session.commit() |
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275 session.close() |
| 538 | 276 else: |
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277 session.add(d_self) #so session knows about us |
| 538 | 278 session.delete(d_self) |
| 279 | |
| 280 # helper routine by update() and __setitem__ | |
| 281 def _set_in_session(d_self, key, val, session): | |
| 282 """Modify an existing key or create a key to hold val""" | |
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283 #FIRST SOME MIRRORING HACKS |
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284 if key == 'dbdict.status': |
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285 ival = int(val) |
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286 d_self.status = ival |
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287 if key == 'dbdict.priority': |
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288 fval = float(val) |
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289 d_self.priority = fval |
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290 |
| 538 | 291 if key in d_self._forbidden_keys: |
| 292 raise KeyError(key) | |
| 293 created = None | |
| 294 for i,a in enumerate(d_self._attrs): | |
| 295 if a.name == key: | |
| 296 assert created == None | |
| 297 created = h_self._KeyVal(key, val) | |
| 298 d_self._attrs[i] = created | |
| 299 if not created: | |
| 300 created = h_self._KeyVal(key, val) | |
| 301 d_self._attrs.append(created) | |
| 302 session.save(created) | |
| 303 | |
| 304 mapper(Dict, dict_table, | |
| 305 properties = { | |
| 306 '_attrs': relation(KeyVal, | |
| 307 secondary=link_table, | |
| 308 cascade="all, delete-orphan") | |
| 309 }) | |
| 310 | |
| 311 class _Query (object): | |
| 312 """ | |
| 313 Attributes: | |
| 314 _query - SqlAlchemy.Query object | |
| 315 """ | |
| 316 | |
| 317 def __init__(q_self, query): | |
| 318 q_self._query = query | |
| 319 | |
| 320 def __iter__(q_self): | |
| 321 return q_self.all().__iter__() | |
| 322 | |
| 323 def __getitem__(q_self, item): | |
| 324 return q_self._query.__getitem__(item) | |
| 325 | |
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326 def filter_eq(q_self, kw, arg): |
| 538 | 327 """Return a Query object that restricts to dictionaries containing |
| 328 the given kwargs""" | |
| 329 | |
| 330 #Note: when we add new types to the key columns, add them here | |
| 331 q = q_self._query | |
| 332 T = h_self._Dict | |
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333 if isinstance(arg, (str,unicode)): |
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334 q = q.filter(T._attrs.any(name=kw, sval=arg)) |
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335 else: |
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336 try: |
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337 f = float(arg) |
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338 except (TypeError, ValueError): |
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339 f = None |
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340 if f is None: |
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341 q = q.filter(T._attrs.any(name=kw, bval=repr(arg))) |
| 538 | 342 else: |
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343 q = q.filter(T._attrs.any(name=kw, fval=f)) |
| 538 | 344 |
| 345 return h_self._Query(q) | |
| 346 | |
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347 def filter_eq_dct(q_self, dct): |
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348 rval = q_self |
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349 for key, val in dct.items(): |
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350 rval = rval.filter_eq(key,val) |
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351 return rval |
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352 |
| 538 | 353 def all(q_self): |
| 354 """Return an iterator over all matching dictionaries. | |
| 355 | |
| 356 See L{SqlAlchemy.Query} | |
| 357 """ | |
| 358 return q_self._query.all() | |
| 359 | |
| 360 def count(q_self): | |
| 361 """Return the number of matching dictionaries. | |
| 362 | |
| 363 See L{SqlAlchemy.Query} | |
| 364 """ | |
| 365 return q_self._query.count() | |
| 366 | |
| 367 def first(q_self): | |
| 368 """Return some matching dictionary, or None | |
| 369 See L{SqlAlchemy.Query} | |
| 370 """ | |
| 371 return q_self._query.first() | |
| 372 | |
| 373 def all_ordered_by(q_self, key, desc=False): | |
| 374 """Return query results, sorted. | |
| 375 | |
| 376 @type key: string or tuple of string or list of string | |
| 377 @param: keys by which to sort the results. | |
| 378 | |
| 379 @rtype: list of L{DbHandle._Dict} instances | |
| 380 @return: query results, sorted by given keys | |
| 381 """ | |
| 382 | |
| 383 # order_by is not easy to do in SQL based on the data structures we're | |
| 384 # using. Considering we support different data types, it may not be | |
| 385 # possible at all. | |
| 386 # | |
| 387 # It would be easy if 'pivot' or 'crosstab' were provided as part of the | |
| 388 # underlying API, but they are not. For example, read this: | |
| 389 # http://www.simple-talk.com/sql/t-sql-programming/creating-cross-tab-queries-and-pivot-tables-in-sql/ | |
| 390 | |
| 391 # load query results | |
| 392 results = list(q_self.all()) | |
| 393 | |
| 394 if isinstance(key, (tuple, list)): | |
| 395 val_results = [([d[k] for k in key], d) for d in results] | |
| 396 else: | |
| 397 val_results = [(d[key], d) for d in results] | |
| 398 | |
| 399 val_results.sort() #interesting: there is an optional key parameter | |
| 400 if desc: | |
| 401 val_results.reverse() | |
| 402 return [vr[-1] for vr in val_results] | |
| 403 | |
| 404 h_self._KeyVal = KeyVal | |
| 405 h_self._Dict = Dict | |
| 406 h_self._Query = _Query | |
| 407 | |
| 408 def __iter__(h_self): | |
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409 return h_self.query.__iter__() |
| 538 | 410 |
| 411 def insert_kwargs(h_self, **dct): | |
| 412 """ | |
| 413 @rtype: DbHandle with reference to self | |
| 414 @return: a DbHandle initialized as a copy of dct | |
| 415 | |
| 416 @type dct: dict-like instance whose keys are strings, and values are | |
| 417 either strings, integers, floats | |
| 418 | |
| 419 @param dct: dictionary to insert | |
| 420 | |
| 421 """ | |
| 422 rval = h_self._Dict() | |
| 423 if dct: rval.update(dct) | |
| 424 return rval | |
| 425 def insert(h_self, dct): | |
| 426 """ | |
| 427 @rtype: DbHandle with reference to self | |
| 428 @return: a DbHandle initialized as a copy of dct | |
| 429 | |
| 430 @type dct: dict-like instance whose keys are strings, and values are | |
| 431 either strings, integers, floats | |
| 432 | |
| 433 @param dct: dictionary to insert | |
| 434 | |
| 435 """ | |
| 436 rval = h_self._Dict() | |
| 437 if dct: rval.update(dct) | |
| 438 return rval | |
| 439 | |
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440 def query(h_self, session): |
| 538 | 441 """Construct an SqlAlchemy query, which can be subsequently filtered |
| 442 using the instance methods of DbQuery""" | |
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443 return h_self._Query(session.query(h_self._Dict)\ |
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444 .options(eagerload('_attrs'))) |
| 538 | 445 |
| 446 def createView(h_self, view): | |
| 447 | |
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448 s = h_self.session() |
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449 cols = [] |
| 538 | 450 |
| 451 for col in view.columns: | |
| 452 if col.name is "id": | |
| 453 continue; | |
| 454 elif isinstance(col.type, (Integer,Float)): | |
| 455 cols.append([col.name,'fval']); | |
| 456 elif isinstance(col.type,String): | |
| 457 cols.append([col.name,'sval']); | |
| 458 elif isinstance(col.type,Binary): | |
| 459 cols.append([col.name,'bval']); | |
| 460 else: | |
| 461 assert "Error: wrong column type in view",view.name; | |
| 462 | |
| 463 # generate raw sql command string | |
| 464 viewsql = crazy_sql_command(view.name, cols, \ | |
| 465 h_self._pair_table.name, \ | |
| 466 h_self._link_table.name); | |
| 467 | |
| 468 #print 'Creating sql view with command:\n', viewsql; | |
| 469 | |
| 470 h_self._engine.execute(viewsql); | |
| 471 s.commit(); | |
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472 s.close() |
| 538 | 473 |
| 474 class MappedClass(object): | |
| 475 pass | |
| 476 | |
| 477 mapper(MappedClass, view) | |
| 478 | |
| 479 return MappedClass | |
| 480 | |
| 481 def session(h_self): | |
| 482 return h_self._session_fn() | |
| 483 | |
| 484 | |
| 485 def db_from_engine(engine, | |
| 486 table_prefix='DbHandle_default_', | |
| 487 trial_suffix='trial', | |
| 488 keyval_suffix='keyval', | |
| 489 link_suffix='link'): | |
| 490 """Create a DbHandle instance | |
| 491 | |
| 492 @type engine: sqlalchemy engine (e.g. from create_engine) | |
| 493 @param engine: connect to this database for transactions | |
| 494 | |
| 495 @type table_prefix: string | |
| 496 @type trial_suffix: string | |
| 497 @type keyval_suffix: string | |
| 498 @type link_suffix: string | |
| 499 | |
| 500 @rtype: DbHandle instance | |
| 501 | |
| 502 @note: The returned DbHandle will use three tables to implement the | |
| 503 many-to-many pattern that it needs: | |
| 504 - I{table_prefix + trial_suffix}, | |
| 505 - I{table_prefix + keyval_suffix} | |
| 506 - I{table_prefix + link_suffix} | |
| 507 | |
| 508 """ | |
| 509 Session = sessionmaker(autoflush=True, autocommit=False) | |
| 510 | |
| 511 metadata = MetaData() | |
| 512 | |
| 513 t_trial = Table(table_prefix+trial_suffix, metadata, | |
| 514 Column('id', Integer, primary_key=True), | |
| 515 Column('create', DateTime), | |
| 516 Column('write', DateTime), | |
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517 Column('read', DateTime), |
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518 Column('status', Integer), |
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519 Column('priority', Float(53)) |
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520 ) |
| 538 | 521 |
| 522 t_keyval = Table(table_prefix+keyval_suffix, metadata, | |
| 523 Column('id', Integer, primary_key=True), | |
| 524 Column('name', String(128), nullable=False), #name of attribute | |
| 525 Column('ntype', Boolean), | |
| 526 Column('fval', Float(53)), | |
| 527 Column('sval', Text), | |
| 528 Column('bval', Binary)) | |
| 529 | |
| 530 t_link = Table(table_prefix+link_suffix, metadata, | |
| 531 Column('dict_id', Integer, ForeignKey('%s.id' % t_trial), | |
| 532 primary_key=True), | |
| 533 Column('pair_id', Integer, ForeignKey('%s.id' % t_keyval), | |
| 534 primary_key=True)) | |
| 535 | |
| 536 metadata.bind = engine | |
| 537 metadata.create_all() # no-op when tables already exist | |
| 538 #warning: tables can exist, but have incorrect schema | |
| 539 # see bug mentioned in DbHandle constructor | |
| 540 | |
| 541 return DbHandle(Session, engine, t_trial, t_keyval, t_link) | |
| 542 | |
| 543 def sqlite_memory_db(echo=False, **kwargs): | |
| 544 """Return a DbHandle backed by a memory-based database""" | |
| 545 engine = create_engine('sqlite:///:memory:', echo=False) | |
| 546 return db_from_engine(engine, **kwargs) | |
| 547 | |
| 548 def sqlite_file_db(filename, echo=False, **kwargs): | |
| 549 """Return a DbHandle backed by a file-based database""" | |
| 550 engine = create_engine('sqlite:///%s' % filename, echo=False) | |
| 551 return db_from_engine(engine, **kwargs) | |
| 552 | |
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553 def postgres_db(user, password, host, database, echo=False, poolclass=sqlalchemy.pool.NullPool, **kwargs): |
| 538 | 554 """Create an engine to access a postgres_dbhandle |
| 555 """ | |
| 556 db_str ='postgres://%(user)s:%(password)s@%(host)s/%(database)s' % locals() | |
| 557 | |
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558 engine = create_engine(db_str, pool_size=pool_size, echo=echo, poolclass=poolclass) |
| 538 | 559 |
| 560 return db_from_engine(engine, **kwargs) | |
| 561 |