/usr/lib/python2.7/dist-packages/migrate/changeset/schema.py is in python-migrate 0.10.0-3ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 | """
Schema module providing common schema operations.
"""
import abc
try: # Python 3
from collections import MutableMapping as DictMixin
except ImportError: # Python 2
from UserDict import DictMixin
import warnings
import six
import sqlalchemy
from sqlalchemy.schema import ForeignKeyConstraint
from sqlalchemy.schema import UniqueConstraint
from migrate.exceptions import *
from migrate.changeset import SQLA_07, SQLA_08
from migrate.changeset import util
from migrate.changeset.databases.visitor import (get_engine_visitor,
run_single_visitor)
__all__ = [
'create_column',
'drop_column',
'alter_column',
'rename_table',
'rename_index',
'ChangesetTable',
'ChangesetColumn',
'ChangesetIndex',
'ChangesetDefaultClause',
'ColumnDelta',
]
def create_column(column, table=None, *p, **kw):
"""Create a column, given the table.
API to :meth:`ChangesetColumn.create`.
"""
if table is not None:
return table.create_column(column, *p, **kw)
return column.create(*p, **kw)
def drop_column(column, table=None, *p, **kw):
"""Drop a column, given the table.
API to :meth:`ChangesetColumn.drop`.
"""
if table is not None:
return table.drop_column(column, *p, **kw)
return column.drop(*p, **kw)
def rename_table(table, name, engine=None, **kw):
"""Rename a table.
If Table instance is given, engine is not used.
API to :meth:`ChangesetTable.rename`.
:param table: Table to be renamed.
:param name: New name for Table.
:param engine: Engine instance.
:type table: string or Table instance
:type name: string
:type engine: obj
"""
table = _to_table(table, engine)
table.rename(name, **kw)
def rename_index(index, name, table=None, engine=None, **kw):
"""Rename an index.
If Index instance is given,
table and engine are not used.
API to :meth:`ChangesetIndex.rename`.
:param index: Index to be renamed.
:param name: New name for index.
:param table: Table to which Index is reffered.
:param engine: Engine instance.
:type index: string or Index instance
:type name: string
:type table: string or Table instance
:type engine: obj
"""
index = _to_index(index, table, engine)
index.rename(name, **kw)
def alter_column(*p, **k):
"""Alter a column.
This is a helper function that creates a :class:`ColumnDelta` and
runs it.
:argument column:
The name of the column to be altered or a
:class:`ChangesetColumn` column representing it.
:param table:
A :class:`~sqlalchemy.schema.Table` or table name to
for the table where the column will be changed.
:param engine:
The :class:`~sqlalchemy.engine.base.Engine` to use for table
reflection and schema alterations.
:returns: A :class:`ColumnDelta` instance representing the change.
"""
if 'table' not in k and isinstance(p[0], sqlalchemy.Column):
k['table'] = p[0].table
if 'engine' not in k:
k['engine'] = k['table'].bind
# deprecation
if len(p) >= 2 and isinstance(p[1], sqlalchemy.Column):
warnings.warn(
"Passing a Column object to alter_column is deprecated."
" Just pass in keyword parameters instead.",
MigrateDeprecationWarning
)
engine = k['engine']
# enough tests seem to break when metadata is always altered
# that this crutch has to be left in until they can be sorted
# out
k['alter_metadata']=True
delta = ColumnDelta(*p, **k)
visitorcallable = get_engine_visitor(engine, 'schemachanger')
engine._run_visitor(visitorcallable, delta)
return delta
def _to_table(table, engine=None):
"""Return if instance of Table, else construct new with metadata"""
if isinstance(table, sqlalchemy.Table):
return table
# Given: table name, maybe an engine
meta = sqlalchemy.MetaData()
if engine is not None:
meta.bind = engine
return sqlalchemy.Table(table, meta)
def _to_index(index, table=None, engine=None):
"""Return if instance of Index, else construct new with metadata"""
if isinstance(index, sqlalchemy.Index):
return index
# Given: index name; table name required
table = _to_table(table, engine)
ret = sqlalchemy.Index(index)
ret.table = table
return ret
# Python3: if we just use:
#
# class ColumnDelta(DictMixin, sqlalchemy.schema.SchemaItem):
# ...
#
# We get the following error:
# TypeError: metaclass conflict: the metaclass of a derived class must be a
# (non-strict) subclass of the metaclasses of all its bases.
#
# The complete inheritance/metaclass relationship list of ColumnDelta can be
# summarized by this following dot file:
#
# digraph test123 {
# ColumnDelta -> MutableMapping;
# MutableMapping -> Mapping;
# Mapping -> {Sized Iterable Container};
# {Sized Iterable Container} -> ABCMeta[style=dashed];
#
# ColumnDelta -> SchemaItem;
# SchemaItem -> {SchemaEventTarget Visitable};
# SchemaEventTarget -> object;
# Visitable -> {VisitableType object} [style=dashed];
# VisitableType -> type;
# }
#
# We need to use a metaclass that inherits from all the metaclasses of
# DictMixin and sqlalchemy.schema.SchemaItem. Let's call it "MyMeta".
class MyMeta(sqlalchemy.sql.visitors.VisitableType, abc.ABCMeta, object):
pass
class ColumnDelta(six.with_metaclass(MyMeta, DictMixin, sqlalchemy.schema.SchemaItem)):
"""Extracts the differences between two columns/column-parameters
May receive parameters arranged in several different ways:
* **current_column, new_column, \*p, \*\*kw**
Additional parameters can be specified to override column
differences.
* **current_column, \*p, \*\*kw**
Additional parameters alter current_column. Table name is extracted
from current_column object.
Name is changed to current_column.name from current_name,
if current_name is specified.
* **current_col_name, \*p, \*\*kw**
Table kw must specified.
:param table: Table at which current Column should be bound to.\
If table name is given, reflection will be used.
:type table: string or Table instance
:param metadata: A :class:`MetaData` instance to store
reflected table names
:param engine: When reflecting tables, either engine or metadata must \
be specified to acquire engine object.
:type engine: :class:`Engine` instance
:returns: :class:`ColumnDelta` instance provides interface for altered attributes to \
`result_column` through :func:`dict` alike object.
* :class:`ColumnDelta`.result_column is altered column with new attributes
* :class:`ColumnDelta`.current_name is current name of column in db
"""
# Column attributes that can be altered
diff_keys = ('name', 'type', 'primary_key', 'nullable',
'server_onupdate', 'server_default', 'autoincrement')
diffs = dict()
__visit_name__ = 'column'
def __init__(self, *p, **kw):
# 'alter_metadata' is not a public api. It exists purely
# as a crutch until the tests that fail when 'alter_metadata'
# behaviour always happens can be sorted out
self.alter_metadata = kw.pop("alter_metadata", False)
self.meta = kw.pop("metadata", None)
self.engine = kw.pop("engine", None)
# Things are initialized differently depending on how many column
# parameters are given. Figure out how many and call the appropriate
# method.
if len(p) >= 1 and isinstance(p[0], sqlalchemy.Column):
# At least one column specified
if len(p) >= 2 and isinstance(p[1], sqlalchemy.Column):
# Two columns specified
diffs = self.compare_2_columns(*p, **kw)
else:
# Exactly one column specified
diffs = self.compare_1_column(*p, **kw)
else:
# Zero columns specified
if not len(p) or not isinstance(p[0], six.string_types):
raise ValueError("First argument must be column name")
diffs = self.compare_parameters(*p, **kw)
self.apply_diffs(diffs)
def __repr__(self):
return '<ColumnDelta altermetadata=%r, %s>' % (
self.alter_metadata,
super(ColumnDelta, self).__repr__()
)
def __getitem__(self, key):
if key not in self.keys():
raise KeyError("No such diff key, available: %s" % self.diffs )
return getattr(self.result_column, key)
def __setitem__(self, key, value):
if key not in self.keys():
raise KeyError("No such diff key, available: %s" % self.diffs )
setattr(self.result_column, key, value)
def __delitem__(self, key):
raise NotImplementedError
def __len__(self):
raise NotImplementedError
def __iter__(self):
raise NotImplementedError
def keys(self):
return self.diffs.keys()
def compare_parameters(self, current_name, *p, **k):
"""Compares Column objects with reflection"""
self.table = k.pop('table')
self.result_column = self._table.c.get(current_name)
if len(p):
k = self._extract_parameters(p, k, self.result_column)
return k
def compare_1_column(self, col, *p, **k):
"""Compares one Column object"""
self.table = k.pop('table', None)
if self.table is None:
self.table = col.table
self.result_column = col
if len(p):
k = self._extract_parameters(p, k, self.result_column)
return k
def compare_2_columns(self, old_col, new_col, *p, **k):
"""Compares two Column objects"""
self.process_column(new_col)
self.table = k.pop('table', None)
# we cannot use bool() on table in SA06
if self.table is None:
self.table = old_col.table
if self.table is None:
new_col.table
self.result_column = old_col
# set differences
# leave out some stuff for later comp
for key in (set(self.diff_keys) - set(('type',))):
val = getattr(new_col, key, None)
if getattr(self.result_column, key, None) != val:
k.setdefault(key, val)
# inspect types
if not self.are_column_types_eq(self.result_column.type, new_col.type):
k.setdefault('type', new_col.type)
if len(p):
k = self._extract_parameters(p, k, self.result_column)
return k
def apply_diffs(self, diffs):
"""Populate dict and column object with new values"""
self.diffs = diffs
for key in self.diff_keys:
if key in diffs:
setattr(self.result_column, key, diffs[key])
self.process_column(self.result_column)
# create an instance of class type if not yet
if 'type' in diffs and callable(self.result_column.type):
self.result_column.type = self.result_column.type()
# add column to the table
if self.table is not None and self.alter_metadata:
self.result_column.add_to_table(self.table)
def are_column_types_eq(self, old_type, new_type):
"""Compares two types to be equal"""
ret = old_type.__class__ == new_type.__class__
# String length is a special case
if ret and isinstance(new_type, sqlalchemy.types.String):
ret = (getattr(old_type, 'length', None) == \
getattr(new_type, 'length', None))
return ret
def _extract_parameters(self, p, k, column):
"""Extracts data from p and modifies diffs"""
p = list(p)
while len(p):
if isinstance(p[0], six.string_types):
k.setdefault('name', p.pop(0))
elif isinstance(p[0], sqlalchemy.types.TypeEngine):
k.setdefault('type', p.pop(0))
elif callable(p[0]):
p[0] = p[0]()
else:
break
if len(p):
new_col = column.copy_fixed()
new_col._init_items(*p)
k = self.compare_2_columns(column, new_col, **k)
return k
def process_column(self, column):
"""Processes default values for column"""
# XXX: this is a snippet from SA processing of positional parameters
toinit = list()
if column.server_default is not None:
if isinstance(column.server_default, sqlalchemy.FetchedValue):
toinit.append(column.server_default)
else:
toinit.append(sqlalchemy.DefaultClause(column.server_default))
if column.server_onupdate is not None:
if isinstance(column.server_onupdate, FetchedValue):
toinit.append(column.server_default)
else:
toinit.append(sqlalchemy.DefaultClause(column.server_onupdate,
for_update=True))
if toinit:
column._init_items(*toinit)
def _get_table(self):
return getattr(self, '_table', None)
def _set_table(self, table):
if isinstance(table, six.string_types):
if self.alter_metadata:
if not self.meta:
raise ValueError("metadata must be specified for table"
" reflection when using alter_metadata")
meta = self.meta
if self.engine:
meta.bind = self.engine
else:
if not self.engine and not self.meta:
raise ValueError("engine or metadata must be specified"
" to reflect tables")
if not self.engine:
self.engine = self.meta.bind
meta = sqlalchemy.MetaData(bind=self.engine)
self._table = sqlalchemy.Table(table, meta, autoload=True)
elif isinstance(table, sqlalchemy.Table):
self._table = table
if not self.alter_metadata:
self._table.meta = sqlalchemy.MetaData(bind=self._table.bind)
def _get_result_column(self):
return getattr(self, '_result_column', None)
def _set_result_column(self, column):
"""Set Column to Table based on alter_metadata evaluation."""
self.process_column(column)
if not hasattr(self, 'current_name'):
self.current_name = column.name
if self.alter_metadata:
self._result_column = column
else:
self._result_column = column.copy_fixed()
table = property(_get_table, _set_table)
result_column = property(_get_result_column, _set_result_column)
class ChangesetTable(object):
"""Changeset extensions to SQLAlchemy tables."""
def create_column(self, column, *p, **kw):
"""Creates a column.
The column parameter may be a column definition or the name of
a column in this table.
API to :meth:`ChangesetColumn.create`
:param column: Column to be created
:type column: Column instance or string
"""
if not isinstance(column, sqlalchemy.Column):
# It's a column name
column = getattr(self.c, str(column))
column.create(table=self, *p, **kw)
def drop_column(self, column, *p, **kw):
"""Drop a column, given its name or definition.
API to :meth:`ChangesetColumn.drop`
:param column: Column to be droped
:type column: Column instance or string
"""
if not isinstance(column, sqlalchemy.Column):
# It's a column name
try:
column = getattr(self.c, str(column))
except AttributeError:
# That column isn't part of the table. We don't need
# its entire definition to drop the column, just its
# name, so create a dummy column with the same name.
column = sqlalchemy.Column(str(column), sqlalchemy.Integer())
column.drop(table=self, *p, **kw)
def rename(self, name, connection=None, **kwargs):
"""Rename this table.
:param name: New name of the table.
:type name: string
:param connection: reuse connection istead of creating new one.
:type connection: :class:`sqlalchemy.engine.base.Connection` instance
"""
engine = self.bind
self.new_name = name
visitorcallable = get_engine_visitor(engine, 'schemachanger')
run_single_visitor(engine, visitorcallable, self, connection, **kwargs)
# Fix metadata registration
self.name = name
self.deregister()
self._set_parent(self.metadata)
def _meta_key(self):
"""Get the meta key for this table."""
return sqlalchemy.schema._get_table_key(self.name, self.schema)
def deregister(self):
"""Remove this table from its metadata"""
if SQLA_07:
self.metadata._remove_table(self.name, self.schema)
else:
key = self._meta_key()
meta = self.metadata
if key in meta.tables:
del meta.tables[key]
class ChangesetColumn(object):
"""Changeset extensions to SQLAlchemy columns."""
def alter(self, *p, **k):
"""Makes a call to :func:`alter_column` for the column this
method is called on.
"""
if 'table' not in k:
k['table'] = self.table
if 'engine' not in k:
k['engine'] = k['table'].bind
return alter_column(self, *p, **k)
def create(self, table=None, index_name=None, unique_name=None,
primary_key_name=None, populate_default=True, connection=None, **kwargs):
"""Create this column in the database.
Assumes the given table exists. ``ALTER TABLE ADD COLUMN``,
for most databases.
:param table: Table instance to create on.
:param index_name: Creates :class:`ChangesetIndex` on this column.
:param unique_name: Creates :class:\
`~migrate.changeset.constraint.UniqueConstraint` on this column.
:param primary_key_name: Creates :class:\
`~migrate.changeset.constraint.PrimaryKeyConstraint` on this column.
:param populate_default: If True, created column will be \
populated with defaults
:param connection: reuse connection istead of creating new one.
:type table: Table instance
:type index_name: string
:type unique_name: string
:type primary_key_name: string
:type populate_default: bool
:type connection: :class:`sqlalchemy.engine.base.Connection` instance
:returns: self
"""
self.populate_default = populate_default
self.index_name = index_name
self.unique_name = unique_name
self.primary_key_name = primary_key_name
for cons in ('index_name', 'unique_name', 'primary_key_name'):
self._check_sanity_constraints(cons)
self.add_to_table(table)
engine = self.table.bind
visitorcallable = get_engine_visitor(engine, 'columngenerator')
engine._run_visitor(visitorcallable, self, connection, **kwargs)
# TODO: reuse existing connection
if self.populate_default and self.default is not None:
stmt = table.update().values({self: engine._execute_default(self.default)})
engine.execute(stmt)
return self
def drop(self, table=None, connection=None, **kwargs):
"""Drop this column from the database, leaving its table intact.
``ALTER TABLE DROP COLUMN``, for most databases.
:param connection: reuse connection istead of creating new one.
:type connection: :class:`sqlalchemy.engine.base.Connection` instance
"""
if table is not None:
self.table = table
engine = self.table.bind
visitorcallable = get_engine_visitor(engine, 'columndropper')
engine._run_visitor(visitorcallable, self, connection, **kwargs)
self.remove_from_table(self.table, unset_table=False)
self.table = None
return self
def add_to_table(self, table):
if table is not None and self.table is None:
if SQLA_07:
table.append_column(self)
else:
self._set_parent(table)
def _col_name_in_constraint(self,cons,name):
return False
def remove_from_table(self, table, unset_table=True):
# TODO: remove primary keys, constraints, etc
if unset_table:
self.table = None
to_drop = set()
for index in table.indexes:
columns = []
for col in index.columns:
if col.name!=self.name:
columns.append(col)
if columns:
index.columns = columns
if SQLA_08:
index.expressions = columns
else:
to_drop.add(index)
table.indexes = table.indexes - to_drop
to_drop = set()
for cons in table.constraints:
# TODO: deal with other types of constraint
if isinstance(cons,(ForeignKeyConstraint,
UniqueConstraint)):
for col_name in cons.columns:
if not isinstance(col_name,six.string_types):
col_name = col_name.name
if self.name==col_name:
to_drop.add(cons)
table.constraints = table.constraints - to_drop
if table.c.contains_column(self):
if SQLA_07:
table._columns.remove(self)
else:
table.c.remove(self)
# TODO: this is fixed in 0.6
def copy_fixed(self, **kw):
"""Create a copy of this ``Column``, with all attributes."""
q = util.safe_quote(self)
return sqlalchemy.Column(self.name, self.type, self.default,
key=self.key,
primary_key=self.primary_key,
nullable=self.nullable,
quote=q,
index=self.index,
unique=self.unique,
onupdate=self.onupdate,
autoincrement=self.autoincrement,
server_default=self.server_default,
server_onupdate=self.server_onupdate,
*[c.copy(**kw) for c in self.constraints])
def _check_sanity_constraints(self, name):
"""Check if constraints names are correct"""
obj = getattr(self, name)
if (getattr(self, name[:-5]) and not obj):
raise InvalidConstraintError("Column.create() accepts index_name,"
" primary_key_name and unique_name to generate constraints")
if not isinstance(obj, six.string_types) and obj is not None:
raise InvalidConstraintError(
"%s argument for column must be constraint name" % name)
class ChangesetIndex(object):
"""Changeset extensions to SQLAlchemy Indexes."""
__visit_name__ = 'index'
def rename(self, name, connection=None, **kwargs):
"""Change the name of an index.
:param name: New name of the Index.
:type name: string
:param connection: reuse connection istead of creating new one.
:type connection: :class:`sqlalchemy.engine.base.Connection` instance
"""
engine = self.table.bind
self.new_name = name
visitorcallable = get_engine_visitor(engine, 'schemachanger')
engine._run_visitor(visitorcallable, self, connection, **kwargs)
self.name = name
class ChangesetDefaultClause(object):
"""Implements comparison between :class:`DefaultClause` instances"""
def __eq__(self, other):
if isinstance(other, self.__class__):
if self.arg == other.arg:
return True
def __ne__(self, other):
return not self.__eq__(other)
|