# mapper.py
# Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Michael Bayer mike_mp@zzzcomputing.com
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""Logic to map Python classes to and from selectables.
Defines the :class:`~sqlalchemy.orm.mapper.Mapper` class, the central configurational
unit which associates a class with a database table.
This is a semi-private module; the main configurational API of the ORM is
available in :class:`~sqlalchemy.orm.`.
"""
import types
import weakref
import operator
from itertools import chain
deque = __import__('collections').deque
from sqlalchemy import sql,util,log,exc
from sqlalchemy.sql import expression,visitors,operators,util
from sqlalchemy.orm import attributes,sync,exc
from sqlalchemy.orm.interfaces import (
MapperProperty, EXT_CONTINUE, PropComparator
)
from sqlalchemy.orm.util import (
ExtensionCarrier, _INSTRUMENTOR, _class_to_mapper, _state_has_identity,
_state_mapper, class_mapper, instance_str, state_str,
)
__all__ = (
'Mapper',
'_mapper_registry',
'class_mapper',
'object_mapper',
)
_mapper_registry = weakref.WeakKeyDictionary()
_new_mappers = False
_already_compiling = False
_none_set = frozenset([None])
# a list of MapperExtensions that will be installed in all mappers by default
global_extensions = []
# a constant returned by _get_attr_by_column to indicate
# this mapper is not handling an attribute for a particular
# column
NO_ATTRIBUTE = util.symbol('NO_ATTRIBUTE')
# lock used to synchronize the "mapper compile" step
_COMPILE_MUTEX = util.threading.RLock()
# initialize these lazily
ColumnProperty = None
SynonymProperty = None
ComparableProperty = None
RelationshipProperty = None
ConcreteInheritedProperty = None
_expire_state = None
_state_session = None
class Mapper(object):
"""Define the correlation of class attributes to database table
columns.
Instances of this class should be constructed via the
:func:`~sqlalchemy.orm.mapper` function.
"""
def __init__(self,
class_,
local_table,
properties = None,
primary_key = None,
non_primary = False,
inherits = None,
inherit_condition = None,
inherit_foreign_keys = None,
extension = None,
order_by = False,
always_refresh = False,
version_id_col = None,
version_id_generator = None,
polymorphic_on=None,
_polymorphic_map=None,
polymorphic_identity=None,
concrete=False,
with_polymorphic=None,
allow_null_pks=None,
allow_partial_pks=True,
batch=True,
column_prefix=None,
include_properties=None,
exclude_properties=None,
passive_updates=True,
eager_defaults=False):
"""Construct a new mapper.
Mappers are normally constructed via the :func:`~sqlalchemy.orm.mapper`
function. See for details.
"""
self.class_ = util.assert_arg_type(class_, type, 'class_')
self.class_manager = None
self.primary_key_argument = primary_key
self.non_primary = non_primary
if order_by is not False:
self.order_by = util.to_list(order_by)
else:
self.order_by = order_by
self.always_refresh = always_refresh
self.version_id_col = version_id_col
self.version_id_generator = version_id_generator or (lambda x:(x or 0) + 1)
self.concrete = concrete
self.single = False
self.inherits = inherits
self.local_table = local_table
self.inherit_condition = inherit_condition
self.inherit_foreign_keys = inherit_foreign_keys
self.extension = extension
self._init_properties = properties or {}
self.delete_orphans = []
self.batch = batch
self.eager_defaults = eager_defaults
self.column_prefix = column_prefix
self.polymorphic_on = polymorphic_on
self._dependency_processors = []
self._validators = {}
self.passive_updates = passive_updates
self._clause_adapter = None
self._requires_row_aliasing = False
self._inherits_equated_pairs = None
if allow_null_pks:
util.warn_deprecated('the allow_null_pks option to Mapper() is '
'deprecated. It is now allow_partial_pks=False|True, '
'defaults to True.')
allow_partial_pks = allow_null_pks
self.allow_partial_pks = allow_partial_pks
if with_polymorphic == '*':
self.with_polymorphic = ('*', None)
elif isinstance(with_polymorphic, (tuple, list)):
if isinstance(with_polymorphic[0], (basestring, tuple, list)):
self.with_polymorphic = with_polymorphic
else:
self.with_polymorphic = (with_polymorphic, None)
elif with_polymorphic is not None:
raise sa_exc.ArgumentError("Invalid setting for with_polymorphic")
else:
self.with_polymorphic = None
if isinstance(self.local_table, expression._SelectBaseMixin):
raise sa_exc.InvalidRequestError(
"When mapping against a select() construct, map against "
"an alias() of the construct instead."
"This because several databases don't allow a "
"SELECT from a subquery that does not have an alias."
)
if self.with_polymorphic and \
isinstance(self.with_polymorphic[1], expression._SelectBaseMixin):
self.with_polymorphic = (self.with_polymorphic[0], self.with_polymorphic[1].alias())
# our 'polymorphic identity', a string name that when located in a result set row
# indicates this Mapper should be used to construct the object instance for that row.
self.polymorphic_identity = polymorphic_identity
# a dictionary of 'polymorphic identity' names, associating those names with
# Mappers that will be used to construct object instances upon a select operation.
if _polymorphic_map is None:
self.polymorphic_map = {}
else:
self.polymorphic_map = _polymorphic_map
self.include_properties = include_properties
self.exclude_properties = exclude_properties
self.compiled = False
# prevent this mapper from being constructed
# while a compile() is occuring (and defer a compile()
# until construction succeeds)
_COMPILE_MUTEX.acquire()
try:
self._configure_inheritance()
self._configure_extensions()
self._configure_class_instrumentation()
self._configure_properties()
self._configure_pks()
global _new_mappers
_new_mappers = True
self._log("constructed")
finally:
_COMPILE_MUTEX.release()
def _configure_inheritance(self):
"""Configure settings related to inherting and/or inherited mappers being present."""
# a set of all mappers which inherit from this one.
self._inheriting_mappers = set()
if self.inherits:
if isinstance(self.inherits, type):
self.inherits = class_mapper(self.inherits, compile=False)
if not issubclass(self.class_, self.inherits.class_):
raise sa_exc.ArgumentError(
"Class '%s' does not inherit from '%s'" %
(self.class_.__name__, self.inherits.class_.__name__))
if self.non_primary != self.inherits.non_primary:
np = not self.non_primary and "primary" or "non-primary"
raise sa_exc.ArgumentError("Inheritance of %s mapper for class '%s' is "
"only allowed from a %s mapper" % (np, self.class_.__name__, np))
# inherit_condition is optional.
if self.local_table is None:
self.local_table = self.inherits.local_table
self.mapped_table = self.inherits.mapped_table
self.single = True
elif not self.local_table is self.inherits.local_table:
if self.concrete:
self.mapped_table = self.local_table
for mapper in self.iterate_to_root():
if mapper.polymorphic_on is not None:
mapper._requires_row_aliasing = True
else:
if self.inherit_condition is None:
# figure out inherit condition from our table to the immediate table
# of the inherited mapper, not its full table which could pull in other
# stuff we dont want (allows test/inheritance.InheritTest4 to pass)
self.inherit_condition = sqlutil.join_condition(self.inherits.local_table, self.local_table)
self.mapped_table = sql.join(self.inherits.mapped_table, self.local_table, self.inherit_condition)
fks = util.to_set(self.inherit_foreign_keys)
self._inherits_equated_pairs = \
sqlutil.criterion_as_pairs(self.mapped_table.onclause,
consider_as_foreign_keys=fks)
else:
self.mapped_table = self.local_table
if self.polymorphic_identity is not None and not self.concrete:
self._identity_class = self.inherits._identity_class
else:
self._identity_class = self.class_
if self.version_id_col is None:
self.version_id_col = self.inherits.version_id_col
self.version_id_generator = self.inherits.version_id_generator
for mapper in self.iterate_to_root():
util.reset_memoized(mapper, '_equivalent_columns')
util.reset_memoized(mapper, '_sorted_tables')
if self.order_by is False and not self.concrete and self.inherits.order_by is not False:
self.order_by = self.inherits.order_by
self.polymorphic_map = self.inherits.polymorphic_map
self.batch = self.inherits.batch
self.inherits._inheriting_mappers.add(self)
self.base_mapper = self.inherits.base_mapper
self.passive_updates = self.inherits.passive_updates
self._all_tables = self.inherits._all_tables
if self.polymorphic_identity is not None:
self.polymorphic_map[self.polymorphic_identity] = self
if self.polymorphic_on is None:
for mapper in self.iterate_to_root():
# try to set up polymorphic on using correesponding_column(); else leave
# as None
if mapper.polymorphic_on is not None:
self.polymorphic_on = self.mapped_table.corresponding_column(mapper.polymorphic_on)
break
else:
self._all_tables = set()
self.base_mapper = self
self.mapped_table = self.local_table
if self.polymorphic_identity is not None:
self.polymorphic_map[self.polymorphic_identity] = self
self._identity_class = self.class_
if self.mapped_table is None:
raise sa_exc.ArgumentError("Mapper '%s' does not have a mapped_table specified." % self)
def _configure_extensions(self):
"""Go through the global_extensions list as well as the list
of ``MapperExtensions`` specified for this ``Mapper`` and
creates a linked list of those extensions.
"""
extlist = util.OrderedSet()
extension = self.extension
if extension:
for ext_obj in util.to_list(extension):
# local MapperExtensions have already instrumented the class
extlist.add(ext_obj)
if self.inherits:
for ext in self.inherits.extension:
if ext not in extlist:
extlist.add(ext)
else:
for ext in global_extensions:
if isinstance(ext, type):
ext = ext()
if ext not in extlist:
extlist.add(ext)
self.extension = ExtensionCarrier()
for ext in extlist:
self.extension.append(ext)
def _configure_class_instrumentation(self):
"""If this mapper is to be a primary mapper (i.e. the
non_primary flag is not set), associate this Mapper with the
given class_ and entity name.
Subsequent calls to ``class_mapper()`` for the class_/entity
name combination will return this mapper. Also decorate the
`__init__` method on the mapped class to include optional
auto-session attachment logic.
"""
manager = attributes.manager_of_class(self.class_)
if self.non_primary:
if not manager or manager.mapper is None:
raise sa_exc.InvalidRequestError(
"Class %s has no primary mapper configured. Configure "
"a primary mapper first before setting up a non primary "
"Mapper." % self.class_)
self.class_manager = manager
_mapper_registry[self] = True
return
if manager is not None:
assert manager.class_ is self.class_
if manager.mapper:
raise sa_exc.ArgumentError(
"Class '%s' already has a primary mapper defined. "
"Use non_primary=True to "
"create a non primary Mapper. clear_mappers() will "
"remove *all* current mappers from all classes." %
self.class_)
#else:
# a ClassManager may already exist as
# ClassManager.instrument_attribute() creates
# new managers for each subclass if they don't yet exist.
_mapper_registry[self] = True
self.extension.instrument_class(self, self.class_)
if manager is None:
manager = attributes.register_class(self.class_,
deferred_scalar_loader = _load_scalar_attributes
)
self.class_manager = manager
manager.mapper = self
# The remaining members can be added by any mapper, e_name None or not.
if manager.info.get(_INSTRUMENTOR, False):
return
event_registry = manager.events
event_registry.add_listener('on_init', _event_on_init)
event_registry.add_listener('on_init_failure', _event_on_init_failure)
event_registry.add_listener('on_resurrect', _event_on_resurrect)
for key, method in util.iterate_attributes(self.class_):
if isinstance(method, types.FunctionType):
if hasattr(method, '__sa_reconstructor__'):
event_registry.add_listener('on_load', method)
elif hasattr(method, '__sa_validators__'):
for name in method.__sa_validators__:
self._validators[name] = method
if 'reconstruct_instance' in self.extension:
def reconstruct(instance):
self.extension.reconstruct_instance(self, instance)
event_registry.add_listener('on_load', reconstruct)
manager.info[_INSTRUMENTOR] = self
def dispose(self):
# Disable any attribute-based compilation.
self.compiled = True
if hasattr(self, '_compile_failed'):
del self._compile_failed
if not self.non_primary and self.class_manager.mapper is self:
attributes.unregister_class(self.class_)
def _configure_pks(self):
self.tables = sqlutil.find_tables(self.mapped_table)
if not self.tables:
raise sa_exc.InvalidRequestError("Could not find any Table objects in mapped table '%s'" % str(self.mapped_table))
self._pks_by_table = {}
self._cols_by_table = {}
all_cols = util.column_set(chain(*[col.proxy_set for col in self._columntoproperty]))
pk_cols = util.column_set(c for c in all_cols if c.primary_key)
# identify primary key columns which are also mapped by this mapper.
tables = set(self.tables + [self.mapped_table])
self._all_tables.update(tables)
for t in tables:
if t.primary_key and pk_cols.issuperset(t.primary_key):
# ordering is important since it determines the ordering of mapper.primary_key (and therefore query.get())
self._pks_by_table[t] = util.ordered_column_set(t.primary_key).intersection(pk_cols)
self._cols_by_table[t] = util.ordered_column_set(t.c).intersection(all_cols)
# determine cols that aren't expressed within our tables; mark these
# as "read only" properties which are refreshed upon INSERT/UPDATE
self._readonly_props = set(
self._columntoproperty[col]
for col in self._columntoproperty
if not hasattr(col, 'table') or col.table not in self._cols_by_table)
# if explicit PK argument sent, add those columns to the primary key mappings
if self.primary_key_argument:
for k in self.primary_key_argument:
if k.table not in self._pks_by_table:
self._pks_by_table[k.table] = util.OrderedSet()
self._pks_by_table[k.table].add(k)
if self.mapped_table not in self._pks_by_table or len(self._pks_by_table[self.mapped_table]) == 0:
raise sa_exc.ArgumentError("Mapper %s could not assemble any primary "
"key columns for mapped table '%s'" % (self, self.mapped_table.description))
if self.inherits and not self.concrete and not self.primary_key_argument:
# if inheriting, the "primary key" for this mapper is that of the inheriting (unless concrete or explicit)
self.primary_key = self.inherits.primary_key
else:
# determine primary key from argument or mapped_table pks - reduce to the minimal set of columns
if self.primary_key_argument:
primary_key = sqlutil.reduce_columns(
[self.mapped_table.corresponding_column(c) for c in self.primary_key_argument],
ignore_nonexistent_tables=True)
else:
primary_key = sqlutil.reduce_columns(
self._pks_by_table[self.mapped_table], ignore_nonexistent_tables=True)
if len(primary_key) == 0:
raise sa_exc.ArgumentError("Mapper %s could not assemble any primary "
"key columns for mapped table '%s'" % (self, self.mapped_table.description))
self.primary_key = primary_key
self._log("Identified primary key columns: %s", primary_key)
def _configure_properties(self):
# Column and other ClauseElement objects which are mapped
self.columns = self.c = util.OrderedProperties()
# object attribute names mapped to MapperProperty objects
self._props = util.OrderedDict()
# table columns mapped to lists of MapperProperty objects
# using a list allows a single column to be defined as
# populating multiple object attributes
self._columntoproperty = util.column_dict()
# load custom properties
if self._init_properties:
for key, prop in self._init_properties.iteritems():
self._configure_property(key, prop, False)
# pull properties from the inherited mapper if any.
if self.inherits:
for key, prop in self.inherits._props.iteritems():
if key not in self._props and not self._should_exclude(key, key, local=False):
self._adapt_inherited_property(key, prop, False)
# create properties for each column in the mapped table,
# for those columns which don't already map to a property
for column in self.mapped_table.columns:
if column in self._columntoproperty:
continue
column_key = (self.column_prefix or '') + column.key
if self._should_exclude(column.key, column_key, local=self.local_table.c.contains_column(column)):
continue
# adjust the "key" used for this column to that
# of the inheriting mapper
for mapper in self.iterate_to_root():
if column in mapper._columntoproperty:
column_key = mapper._columntoproperty[column].key
self._configure_property(column_key, column, init=False, setparent=True)
# do a special check for the "discriminiator" column, as it may only be present
# in the 'with_polymorphic' selectable but we need it for the base mapper
if self.polymorphic_on is not None and self.polymorphic_on not in self._columntoproperty:
col = self.mapped_table.corresponding_column(self.polymorphic_on)
if col is None:
instrument = False
col = self.polymorphic_on
else:
instrument = True
if self._should_exclude(col.key, col.key, local=False):
raise sa_exc.InvalidRequestError("Cannot exclude or override the discriminator column %r" % col.key)
self._configure_property(col.key, ColumnProperty(col, _instrument=instrument), init=False, setparent=True)
def _adapt_inherited_property(self, key, prop, init):
if not self.concrete:
self._configure_property(key, prop, init=False, setparent=False)
elif key not in self._props:
self._configure_property(key, ConcreteInheritedProperty(), init=init, setparent=True)
def _configure_property(self, key, prop, init=True, setparent=True):
self._log("_configure_property(%s, %s)", key, prop.__class__.__name__)
if not isinstance(prop, MapperProperty):
# we were passed a Column or a list of Columns; generate a ColumnProperty
columns = util.to_list(prop)
column = columns[0]
if not expression.is_column(column):
raise sa_exc.ArgumentError("%s=%r is not an instance of MapperProperty or Column" % (key, prop))
prop = self._props.get(key, None)
if isinstance(prop, ColumnProperty):
# TODO: the "property already exists" case is still not well defined here.
# assuming single-column, etc.
if prop.parent is not self:
# existing ColumnProperty from an inheriting mapper.
# make a copy and append our column to it
prop = prop.copy()
prop.columns.append(column)
self._log("appending to existing ColumnProperty %s" % (key))
elif prop is None or isinstance(prop, ConcreteInheritedProperty):
mapped_column = []
for c in columns:
mc = self.mapped_table.corresponding_column(c)
if mc is None:
mc = self.local_table.corresponding_column(c)
if mc is not None:
# if the column is in the local table but not the mapped table,
# this corresponds to adding a column after the fact to the local table.
# [ticket:1523]
self.mapped_table._reset_exported()
mc = self.mapped_table.corresponding_column(c)
if mc is None:
raise sa_exc.ArgumentError("When configuring property '%s' on %s, "
"column '%s' is not represented in the mapper's table. "
"Use the `column_property()` function to force this column "
"to be mapped as a read-only attribute." % (key, self, c))
mapped_column.append(mc)
prop = ColumnProperty(*mapped_column)
else:
raise sa_exc.ArgumentError("WARNING: when configuring property '%s' on %s, column '%s' "
"conflicts with property '%r'. "
"To resolve this, map the column to the class under a different "
"name in the 'properties' dictionary. Or, to remove all awareness "
"of the column entirely (including its availability as a foreign key), "
"use the 'include_properties' or 'exclude_properties' mapper arguments "
"to control specifically which table columns get mapped." %
(key, self, column.key, prop))
if isinstance(prop, ColumnProperty):
col = self.mapped_table.corresponding_column(prop.columns[0])
# if the column is not present in the mapped table,
# test if a column has been added after the fact to the parent table
# (or their parent, etc.)
# [ticket:1570]
if col is None and self.inherits:
path = [self]
for m in self.inherits.iterate_to_root():
col = m.local_table.corresponding_column(prop.columns[0])
if col is not None:
for m2 in path:
m2.mapped_table._reset_exported()
col = self.mapped_table.corresponding_column(prop.columns[0])
break
path.append(m)
# otherwise, col might not be present! the selectable given
# to the mapper need not include "deferred"
# columns (included in zblog tests)
if col is None:
col = prop.columns[0]
# column is coming in after _readonly_props was initialized; check
# for 'readonly'
if hasattr(self, '_readonly_props') and \
(not hasattr(col, 'table') or col.table not in self._cols_by_table):
self._readonly_props.add(prop)
else:
# if column is coming in after _cols_by_table was initialized, ensure the col is in the
# right set
if hasattr(self, '_cols_by_table') and col.table in self._cols_by_table and col not in self._cols_by_table[col.table]:
self._cols_by_table[col.table].add(col)
# if this ColumnProperty represents the "polymorphic discriminator"
# column, mark it. We'll need this when rendering columns
# in SELECT statements.
if not hasattr(prop, '_is_polymorphic_discriminator'):
prop._is_polymorphic_discriminator = (col is self.polymorphic_on or prop.columns[0] is self.polymorphic_on)
self.columns[key] = col
for col in prop.columns:
for col in col.proxy_set:
self._columntoproperty[col] = prop
elif isinstance(prop, (ComparableProperty, SynonymProperty)) and setparent:
if prop.descriptor is None:
desc = getattr(self.class_, key, None)
if self._is_userland_descriptor(desc):
prop.descriptor = desc
if getattr(prop, 'map_column', False):
if key not in self.mapped_table.c:
raise sa_exc.ArgumentError(
"Can't compile synonym '%s': no column on table '%s' named '%s'"
% (prop.name, self.mapped_table.description, key))
elif self.mapped_table.c[key] in self._columntoproperty and \
self._columntoproperty[self.mapped_table.c[key]].key == prop.name:
raise sa_exc.ArgumentError(
"Can't call map_column=True for synonym %r=%r, "
"a ColumnProperty already exists keyed to the name %r "
"for column %r" %
(key, prop.name, prop.name, key)
)
p = ColumnProperty(self.mapped_table.c[key])
self._configure_property(prop.name, p, init=init, setparent=setparent)
p._mapped_by_synonym = key
if key in self._props and getattr(self._props[key], '_mapped_by_synonym', False):
syn = self._props[key]._mapped_by_synonym
raise sa_exc.ArgumentError(
"Can't call map_column=True for synonym %r=%r, "
"a ColumnProperty already exists keyed to the name "
"%r for column %r" % (syn, key, key, syn)
)
self._props[key] = prop
prop.key = key
if setparent:
prop.set_parent(self)
if not self.non_primary:
prop.instrument_class(self)
for mapper in self._inheriting_mappers:
mapper._adapt_inherited_property(key, prop, init)
if init:
prop.init()
prop.post_instrument_class(self)
def compile(self):
"""Compile this mapper and all other non-compiled mappers.
This method checks the local compiled status as well as for
any new mappers that have been defined, and is safe to call
repeatedly.
"""
global _new_mappers
if self.compiled and not _new_mappers:
return self
_COMPILE_MUTEX.acquire()
try:
try:
global _already_compiling
if _already_compiling:
return
_already_compiling = True
try:
# double-check inside mutex
if self.compiled and not _new_mappers:
return self
# initialize properties on all mappers
# note that _mapper_registry is unordered, which
# may randomly conceal/reveal issues related to
# the order of mapper compilation
for mapper in list(_mapper_registry):
if getattr(mapper, '_compile_failed', False):
raise sa_exc.InvalidRequestError(
"One or more mappers failed to compile. "
"Exception was probably "
"suppressed within a hasattr() call. "
"Message was: %s" % mapper._compile_failed)
if not mapper.compiled:
mapper._post_configure_properties()
_new_mappers = False
return self
finally:
_already_compiling = False
except:
import sys
exc = sys.exc_info()[1]
self._compile_failed = exc
raise
finally:
_COMPILE_MUTEX.release()
def _post_configure_properties(self):
"""Call the ``init()`` method on all ``MapperProperties``
attached to this mapper.
This is a deferred configuration step which is intended
to execute once all mappers have been constructed.
"""
self._log("_post_configure_properties() started")
l = [(key, prop) for key, prop in self._props.iteritems()]
for key, prop in l:
self._log("initialize prop %s", key)
if prop.parent is self and not prop._compile_started:
prop.init()
if prop._compile_finished:
prop.post_instrument_class(self)
self._log("_post_configure_properties() complete")
self.compiled = True
def add_properties(self, dict_of_properties):
"""Add the given dictionary of properties to this mapper,
using `add_property`.
"""
for key, value in dict_of_properties.iteritems():
self.add_property(key, value)
def add_property(self, key, prop):
"""Add an individual MapperProperty to this mapper.
If the mapper has not been compiled yet, just adds the
property to the initial properties dictionary sent to the
constructor. If this Mapper has already been compiled, then
the given MapperProperty is compiled immediately.
"""
self._init_properties[key] = prop
self._configure_property(key, prop, init=self.compiled)
def _log(self, msg, *args):
self.logger.info(
"(" + self.class_.__name__ +
"|" +
(self.local_table is not None and
self.local_table.description or
str(self.local_table)) +
(self.non_primary and "|non-primary" or "") + ") " +
msg, *args)
def _log_debug(self, msg, *args):
self.logger.debug(
"(" + self.class_.__name__ +
"|" +
(self.local_table is not None and
self.local_table.description
or str(self.local_table)) +
(self.non_primary and "|non-primary" or "") + ") " +
msg, *args)
def __repr__(self):
return '<Mapper at 0x%x; %s>' % (
id(self), self.class_.__name__)
def __str__(self):
return "Mapper|%s|%s%s" % (
self.class_.__name__,
self.local_table is not None and self.local_table.description or None,
self.non_primary and "|non-primary" or ""
)
def _is_orphan(self, state):
o = False
for mapper in self.iterate_to_root():
for (key, cls) in mapper.delete_orphans:
if attributes.manager_of_class(cls).has_parent(
state, key, optimistic=_state_has_identity(state)):
return False
o = o or bool(mapper.delete_orphans)
return o
def has_property(self, key):
return key in self._props
def get_property(self, key, resolve_synonyms=False, raiseerr=True):
"""return a MapperProperty associated with the given key."""
if not self.compiled:
self.compile()
return self._get_property(key, resolve_synonyms=resolve_synonyms, raiseerr=raiseerr)
def _get_property(self, key, resolve_synonyms=False, raiseerr=True):
prop = self._props.get(key, None)
if resolve_synonyms:
while isinstance(prop, SynonymProperty):
prop = self._props.get(prop.name, None)
if prop is None and raiseerr:
raise sa_exc.InvalidRequestError("Mapper '%s' has no property '%s'" % (str(self), key))
return prop
@property
def iterate_properties(self):
"""return an iterator of all MapperProperty objects."""
if not self.compiled:
self.compile()
return self._props.itervalues()
def _mappers_from_spec(self, spec, selectable):
"""given a with_polymorphic() argument, return the set of mappers it represents.
Trims the list of mappers to just those represented within the given selectable, if present.
This helps some more legacy-ish mappings.
"""
if spec == '*':
mappers = list(self.polymorphic_iterator())
elif spec:
mappers = [_class_to_mapper(m) for m in util.to_list(spec)]
for m in mappers:
if not m.isa(self):
raise sa_exc.InvalidRequestError("%r does not inherit from %r" % (m, self))
else:
mappers = []
if selectable is not None:
tables = set(sqlutil.find_tables(selectable, include_aliases=True))
mappers = [m for m in mappers if m.local_table in tables]
return mappers
def _selectable_from_mappers(self, mappers):
"""given a list of mappers (assumed to be within this mapper's inheritance hierarchy),
construct an outerjoin amongst those mapper's mapped tables.
"""
from_obj = self.mapped_table
for m in mappers:
if m is self:
continue
if m.concrete:
raise sa_exc.InvalidRequestError("'with_polymorphic()' requires 'selectable' argument when concrete-inheriting mappers are used.")
elif not m.single:
from_obj = from_obj.outerjoin(m.local_table, m.inherit_condition)
return from_obj
@property
def _single_table_criterion(self):
if self.single and \
self.inherits and \
self.polymorphic_on is not None and \
self.polymorphic_identity is not None:
return self.polymorphic_on.in_(
m.polymorphic_identity
for m in self.polymorphic_iterator())
else:
return None
@util.memoized_property
def _with_polymorphic_mappers(self):
if not self.with_polymorphic:
return [self]
return self._mappers_from_spec(*self.with_polymorphic)
@util.memoized_property
def _with_polymorphic_selectable(self):
if not self.with_polymorphic:
return self.mapped_table
spec, selectable = self.with_polymorphic
if selectable is not None:
return selectable
else:
return self._selectable_from_mappers(self._mappers_from_spec(spec, selectable))
def _with_polymorphic_args(self, spec=None, selectable=False):
if self.with_polymorphic:
if not spec:
spec = self.with_polymorphic[0]
if selectable is False:
selectable = self.with_polymorphic[1]
mappers = self._mappers_from_spec(spec, selectable)
if selectable is not None:
return mappers, selectable
else:
return mappers, self._selectable_from_mappers(mappers)
def _iterate_polymorphic_properties(self, mappers=None):
"""Return an iterator of MapperProperty objects which will render into a SELECT."""
if mappers is None:
mappers = self._with_polymorphic_mappers
if not mappers:
for c in self.iterate_properties:
yield c
else:
# in the polymorphic case, filter out discriminator columns
# from other mappers, as these are sometimes dependent on that
# mapper's polymorphic selectable (which we don't want rendered)
for c in util.unique_list(
chain(*[list(mapper.iterate_properties) for mapper in [self] + mappers])
):
if getattr(c, '_is_polymorphic_discriminator', False) and \
(self.polymorphic_on is None or c.columns[0] is not self.polymorphic_on):
continue
yield c
@property
def properties(self):
raise NotImplementedError("Public collection of MapperProperty objects is "
"provided by the get_property() and iterate_properties accessors.")
@util.memoized_property
def _get_clause(self):
"""create a "get clause" based on the primary key. this is used
by query.get() and many-to-one lazyloads to load this item
by primary key.
"""
params = [(primary_key, sql.bindparam(None, type_=primary_key.type)) for primary_key in self.primary_key]
return sql.and_(*[k==v for (k, v) in params]), util.column_dict(params)
@util.memoized_property
def _equivalent_columns(self):
"""Create a map of all *equivalent* columns, based on
the determination of column pairs that are equated to
one another based on inherit condition. This is designed
to work with the queries that util.polymorphic_union
comes up with, which often don't include the columns from
the base table directly (including the subclass table columns
only).
The resulting structure is a dictionary of columns mapped
to lists of equivalent columns, i.e.
{
tablea.col1:
set([tableb.col1, tablec.col1]),
tablea.col2:
set([tabled.col2])
}
"""
result = util.column_dict()
def visit_binary(binary):
if binary.operator == operators.eq:
if binary.left in result:
result[binary.left].add(binary.right)
else:
result[binary.left] = util.column_set((binary.right,))
if binary.right in result:
result[binary.right].add(binary.left)
else:
result[binary.right] = util.column_set((binary.left,))
for mapper in self.base_mapper.polymorphic_iterator():
if mapper.inherit_condition is not None:
visitors.traverse(mapper.inherit_condition, {}, {'binary':visit_binary})
return result
def _is_userland_descriptor(self, obj):
return not isinstance(obj, (MapperProperty, attributes.InstrumentedAttribute)) and hasattr(obj, '__get__')
def _should_exclude(self, name, assigned_name, local):
"""determine whether a particular property should be implicitly present on the class.
This occurs when properties are propagated from an inherited class, or are
applied from the columns present in the mapped table.
"""
# check for descriptors, either local or from
# an inherited class
if local:
if self.class_.__dict__.get(assigned_name, None) is not None\
and self._is_userland_descriptor(self.class_.__dict__[assigned_name]):
return True
else:
if getattr(self.class_, assigned_name, None) is not None\
and self._is_userland_descriptor(getattr(self.class_, assigned_name)):
return True
if (self.include_properties is not None and
name not in self.include_properties):
self._log("not including property %s" % (name))
return True
if (self.exclude_properties is not None and
name in self.exclude_properties):
self._log("excluding property %s" % (name))
return True
return False
def common_parent(self, other):
"""Return true if the given mapper shares a common inherited parent as this mapper."""
return self.base_mapper is other.base_mapper
def _canload(self, state, allow_subtypes):
s = self.primary_mapper()
if self.polymorphic_on is not None or allow_subtypes:
return _state_mapper(state).isa(s)
else:
return _state_mapper(state) is s
def isa(self, other):
"""Return True if the this mapper inherits from the given mapper."""
m = self
while m and m is not other:
m = m.inherits
return bool(m)
def iterate_to_root(self):
m = self
while m:
yield m
m = m.inherits
def polymorphic_iterator(self):
"""Iterate through the collection including this mapper and
all descendant mappers.
This includes not just the immediately inheriting mappers but
all their inheriting mappers as well.
To iterate through an entire hierarchy, use
``mapper.base_mapper.polymorphic_iterator()``.
"""
stack = deque([self])
while stack:
item = stack.popleft()
yield item
stack.extend(item._inheriting_mappers)
def primary_mapper(self):
"""Return the primary mapper corresponding to this mapper's class key (class)."""
return self.class_manager.mapper
@property
def primary_base_mapper(self):
return self.class_manager.mapper.base_mapper
def identity_key_from_row(self, row, adapter=None):
"""Return an identity-map key for use in storing/retrieving an
item from the identity map.
row
A ``sqlalchemy.engine.base.RowProxy`` instance or a
dictionary corresponding result-set ``ColumnElement``
instances to their values within a row.
"""
pk_cols = self.primary_key
if adapter:
pk_cols = [adapter.columns[c] for c in pk_cols]
return (self._identity_class, tuple(row[column] for column in pk_cols))
def identity_key_from_primary_key(self, primary_key):
"""Return an identity-map key for use in storing/retrieving an
item from an identity map.
primary_key
A list of values indicating the identifier.
"""
return (self._identity_class, tuple(util.to_list(primary_key)))
def identity_key_from_instance(self, instance):
"""Return the identity key for the given instance, based on
its primary key attributes.
This value is typically also found on the instance state under the
attribute name `key`.
"""
return self.identity_key_from_primary_key(self.primary_key_from_instance(instance))
def _identity_key_from_state(self, state):
return self.identity_key_from_primary_key(self._primary_key_from_state(state))
def primary_key_from_instance(self, instance):
"""Return the list of primary key values for the given
instance.
"""
state = attributes.instance_state(instance)
return self._primary_key_from_state(state)
def _primary_key_from_state(self, state):
dict_ = state.dict
return [self._get_state_attr_by_column(state, dict_, column) for column in self.primary_key]
def _get_col_to_prop(self, column):
try:
return self._columntoproperty[column]
except KeyError:
prop = self._props.get(column.key, None)
if prop:
raise orm_exc.UnmappedColumnError("Column '%s.%s' is not available, due to conflicting property '%s':%s" % (column.table.name, column.name, column.key, repr(prop)))
else:
raise orm_exc.UnmappedColumnError("No column %s is configured on mapper %s..." % (column, self))
# TODO: improve names?
def _get_state_attr_by_column(self, state, dict_, column):
return self._get_col_to_prop(column)._getattr(state, dict_, column)
def _set_state_attr_by_column(self, state, dict_, column, value):
return self._get_col_to_prop(column)._setattr(state, dict_, value, column)
def _get_committed_attr_by_column(self, obj, column):
state = attributes.instance_state(obj)
dict_ = attributes.instance_dict(obj)
return self._get_committed_state_attr_by_column(state, dict_, column)
def _get_committed_state_attr_by_column(self, state, dict_, column, passive=False):
return self._get_col_to_prop(column)._getcommitted(state, dict_, column, passive=passive)
def _optimized_get_statement(self, state, attribute_names):
"""assemble a WHERE clause which retrieves a given state by primary key, using a minimized set of tables.
Applies to a joined-table inheritance mapper where the
requested attribute names are only present on joined tables,
not the base table. The WHERE clause attempts to include
only those tables to minimize joins.
"""
props = self._props
tables = set(chain(*
(sqlutil.find_tables(props[key].columns[0], check_columns=True)
for key in attribute_names)
))
if self.base_mapper.local_table in tables:
return None
class ColumnsNotAvailable(Exception):
pass
def visit_binary(binary):
leftcol = binary.left
rightcol = binary.right
if leftcol is None or rightcol is None:
return
if leftcol.table not in tables:
leftval = self._get_committed_state_attr_by_column(state, state.dict, leftcol, passive=True)
if leftval is attributes.PASSIVE_NO_RESULT:
raise ColumnsNotAvailable()
binary.left = sql.bindparam(None, leftval, type_=binary.right.type)
elif rightcol.table not in tables:
rightval = self._get_committed_state_attr_by_column(state, state.dict, rightcol, passive=True)
if rightval is attributes.PASSIVE_NO_RESULT:
raise ColumnsNotAvailable()
binary.right = sql.bindparam(None, rightval, type_=binary.right.type)
allconds = []
try:
start = False
for mapper in reversed(list(self.iterate_to_root())):
if mapper.local_table in tables:
start = True
if start and not mapper.single:
allconds.append(visitors.cloned_traverse(mapper.inherit_condition, {}, {'binary':visit_binary}))
except ColumnsNotAvailable:
return None
cond = sql.and_(*allconds)
cols = []
for key in attribute_names:
cols.extend(props[key].columns)
return sql.select(cols, cond, use_labels=True)
def cascade_iterator(self, type_, state, halt_on=None):
"""Iterate each element and its mapper in an object graph,
for all relationships that meet the given cascade rule.
``type\_``:
The name of the cascade rule (i.e. save-update, delete,
etc.)
``state``:
The lead InstanceState. child items will be processed per
the relationships defined for this object's mapper.
the return value are object instances; this provides a strong
reference so that they don't fall out of scope immediately.
"""
visited_instances = util.IdentitySet()
visitables = [(self._props.itervalues(), 'property', state)]
while visitables:
iterator, item_type, parent_state = visitables[-1]
try:
if item_type == 'property':
prop = iterator.next()
visitables.append((prop.cascade_iterator(type_, parent_state,
visited_instances, halt_on), 'mapper', None))
elif item_type == 'mapper':
instance, instance_mapper, corresponding_state = iterator.next()
yield (instance, instance_mapper)
visitables.append((instance_mapper._props.itervalues(),
'property', corresponding_state))
except StopIteration:
visitables.pop()
@util.memoized_property
def _sorted_tables(self):
table_to_mapper = {}
for mapper in self.base_mapper.polymorphic_iterator():
for t in mapper.tables:
table_to_mapper[t] = mapper
sorted_ = sqlutil.sort_tables(table_to_mapper.iterkeys())
ret = util.OrderedDict()
for t in sorted_:
ret[t] = table_to_mapper[t]
return ret
def _per_mapper_flush_actions(self, uow):
saves = unitofwork.SaveUpdateAll(uow, self.base_mapper)
deletes = unitofwork.DeleteAll(uow, self.base_mapper)
uow.dependencies.add((saves, deletes))
for dep in self._dependency_processors:
dep.per_property_preprocessors(uow)
for prop in self._props.values():
prop.per_property_preprocessors(uow)
def _per_state_flush_actions(self, uow, states, isdelete):
base_mapper = self.base_mapper
save_all = unitofwork.SaveUpdateAll(uow, base_mapper)
delete_all = unitofwork.DeleteAll(uow, base_mapper)
for state in states:
# keep saves before deletes -
# this ensures 'row switch' operations work
if isdelete:
action = unitofwork.DeleteState(uow, state, base_mapper)
uow.dependencies.add((save_all, action))
else:
action = unitofwork.SaveUpdateState(uow, state, base_mapper)
uow.dependencies.add((action, delete_all))
yield action
def _save_obj(self, states, uowtransaction, postupdate=False,
post_update_cols=None, single=False):
"""Issue ``INSERT`` and/or ``UPDATE`` statements for a list of objects.
This is called within the context of a UOWTransaction during a
flush operation.
`_save_obj` issues SQL statements not just for instances mapped
directly by this mapper, but for instances mapped by all
inheriting mappers as well. This is to maintain proper insert
ordering among a polymorphic chain of instances. Therefore
_save_obj is typically called only on a *base mapper*, or a
mapper which does not inherit from any other mapper.
"""
# if batch=false, call _save_obj separately for each object
if not single and not self.batch:
for state in _sort_states(states):
self._save_obj([state],
uowtransaction,
postupdate=postupdate,
post_update_cols=post_update_cols,
single=True)
return
# if session has a connection callable,
# organize individual states with the connection
# to use for insert/update
if 'connection_callable' in uowtransaction.mapper_flush_opts:
connection_callable = \
uowtransaction.mapper_flush_opts['connection_callable']
else:
connection = uowtransaction.transaction.connection(self)
connection_callable = None
tups = []
for state in _sort_states(states):
conn = connection_callable and \
connection_callable(self, state.obj()) or \
connection
has_identity = _state_has_identity(state)
mapper = _state_mapper(state)
instance_key = state.key or mapper._identity_key_from_state(state)
row_switch = None
if not postupdate:
# call before_XXX extensions
if not has_identity:
if 'before_insert' in mapper.extension:
mapper.extension.before_insert(mapper, conn, state.obj())
else:
if 'before_update' in mapper.extension:
mapper.extension.before_update(mapper, conn, state.obj())
# detect if we have a "pending" instance (i.e. has
# no instance_key attached to it), and another instance
# with the same identity key already exists as persistent.
# convert to an UPDATE if so.
if not has_identity and \
instance_key in uowtransaction.session.identity_map:
instance = uowtransaction.session.identity_map[instance_key]
existing = attributes.instance_state(instance)
if not uowtransaction.is_deleted(existing):
raise orm_exc.FlushError(
"New instance %s with identity key %s conflicts "
"with persistent instance %s" %
(state_str(state), instance_key, state_str(existing)))
self._log_debug(
"detected row switch for identity %s. "
"will update %s, remove %s from "
"transaction", instance_key,
state_str(state), state_str(existing))
# remove the "delete" flag from the existing element
uowtransaction.remove_state_actions(existing)
row_switch = existing
tups.append(
(state,
state.dict,
mapper,
conn,
has_identity,
instance_key,
row_switch)
)
table_to_mapper = self._sorted_tables
for table in table_to_mapper:
insert = []
update = []
for state, state_dict, mapper, connection, has_identity, \
instance_key, row_switch in tups:
if table not in mapper._pks_by_table:
continue
pks = mapper._pks_by_table[table]
isinsert = not has_identity and \
not postupdate and \
not row_switch
params = {}
value_params = {}
hasdata = False
if isinsert:
for col in mapper._cols_by_table[table]:
if col is mapper.version_id_col:
params[col.key] = mapper.version_id_generator(None)
elif mapper.polymorphic_on is not None and \
mapper.polymorphic_on.shares_lineage(col):
value = mapper.polymorphic_identity
if ((col.default is None and
col.server_default is None) or
value is not None):
params[col.key] = value
elif col in pks:
value = mapper._get_state_attr_by_column(state, state_dict, col)
if value is not None:
params[col.key] = value
else:
value = mapper._get_state_attr_by_column(state, state_dict, col)
if ((col.default is None and
col.server_default is None) or
value is not None):
if isinstance(value, sql.ClauseElement):
value_params[col] = value
else:
params[col.key] = value
insert.append((state, state_dict, params, mapper,
connection, value_params))
else:
for col in mapper._cols_by_table[table]:
if col is mapper.version_id_col:
params[col._label] = \
mapper._get_state_attr_by_column(
row_switch or state,
row_switch and row_switch.dict or state_dict,
col)
params[col.key] = \
mapper.version_id_generator(params[col._label])
# HACK: check for history, in case the history is only
# in a different table than the one where the version_id_col
# is.
for prop in mapper._columntoproperty.itervalues():
history = attributes.get_state_history(
state, prop.key, passive=True)
if history.added:
hasdata = True
elif mapper.polymorphic_on is not None and \
mapper.polymorphic_on.shares_lineage(col) and \
col not in pks:
pass
else:
if post_update_cols is not None and \
col not in post_update_cols:
if col in pks:
params[col._label] = \
mapper._get_state_attr_by_column(state, state_dict, col)
continue
prop = mapper._columntoproperty[col]
history = attributes.get_state_history(state, prop.key, passive=True)
if history.added:
if isinstance(history.added[0], sql.ClauseElement):
value_params[col] = history.added[0]
else:
params[col.key] = prop.get_col_value(col, history.added[0])
if col in pks:
if history.deleted:
# if passive_updates and sync detected this was a
# pk->pk sync, use the new value to locate the row,
# since the DB would already have set this
if ("pk_cascaded", state, col) in \
uowtransaction.attributes:
params[col._label] = \
prop.get_col_value(col, history.added[0])
else:
# use the old value to locate the row
params[col._label] = \
prop.get_col_value(col, history.deleted[0])
hasdata = True
else:
# row switch logic can reach us here
# remove the pk from the update params so the update doesn't
# attempt to include the pk in the update statement
del params[col.key]
params[col._label] = \
prop.get_col_value(col, history.added[0])
else:
hasdata = True
elif col in pks:
params[col._label] = mapper._get_state_attr_by_column(state, state_dict, col)
if hasdata:
update.append((state, state_dict, params, mapper,
connection, value_params))
if update:
mapper = table_to_mapper[table]
clause = sql.and_()
for col in mapper._pks_by_table[table]:
clause.clauses.append(
col ==
sql.bindparam(col._label, type_=col.type)
)
needs_version_id = mapper.version_id_col is not None and \
table.c.contains_column(mapper.version_id_col)
if needs_version_id:
clause.clauses.append(mapper.version_id_col ==\
sql.bindparam(mapper.version_id_col._label, type_=col.type))
statement = table.update(clause)
if len(update) > 1:
compiled_cache = {}
else:
compiled_cache = None
rows = 0
for state, state_dict, params, mapper, connection, value_params in update:
if not value_params and compiled_cache is not None:
c = connection.\
execution_options(
compiled_cache=compiled_cache).\
execute(statement, params)
else:
c = connection.execute(statement.values(value_params), params)
mapper._postfetch(uowtransaction, table,
state, state_dict, c, c.last_updated_params(), value_params)
rows += c.rowcount
if connection.dialect.supports_sane_rowcount:
if rows != len(update):
raise orm_exc.ConcurrentModificationError(
"Updated rowcount %d does not match number "
"of objects updated %d" %
(rows, len(update)))
elif needs_version_id:
util.warn("Dialect %s does not support updated rowcount "
"- versioning cannot be verified." %
c.dialect.dialect_description,
stacklevel=12)
if insert:
statement = table.insert()
if len(insert) > 1:
compiled_cache = {}
else:
compiled_cache = None
for state, state_dict, params, mapper, connection, value_params in insert:
if not value_params and compiled_cache is not None:
c = connection.\
execution_options(
compiled_cache=compiled_cache).\
execute(statement, params)
else:
c = connection.execute(statement.values(value_params), params)
primary_key = c.inserted_primary_key
if primary_key is not None:
# set primary key attributes
for i, col in enumerate(mapper._pks_by_table[table]):
if mapper._get_state_attr_by_column(state, state_dict, col) is None and \
len(primary_key) > i:
mapper._set_state_attr_by_column(state, state_dict, col, primary_key[i])
mapper._postfetch(uowtransaction, table,
state, state_dict, c, c.last_inserted_params(), value_params)
if not postupdate:
for state, state_dict, mapper, connection, has_identity, \
instance_key, row_switch in tups:
# expire readonly attributes
readonly = state.unmodified.intersection(
p.key for p in mapper._readonly_props
)
if readonly:
_expire_state(state, state.dict, readonly)
# if eager_defaults option is enabled,
# refresh whatever has been expired.
if self.eager_defaults and state.unloaded:
state.key = self._identity_key_from_state(state)
uowtransaction.session.query(self)._get(
state.key, refresh_state=state,
only_load_props=state.unloaded)
# call after_XXX extensions
if not has_identity:
if 'after_insert' in mapper.extension:
mapper.extension.after_insert(mapper, connection, state.obj())
else:
if 'after_update' in mapper.extension:
mapper.extension.after_update(mapper, connection, state.obj())
def _postfetch(self, uowtransaction, table,
state, dict_, resultproxy, params, value_params):
"""Expire attributes in need of newly persisted database state."""
postfetch_cols = resultproxy.postfetch_cols()
generated_cols = list(resultproxy.prefetch_cols())
if self.polymorphic_on is not None:
po = table.corresponding_column(self.polymorphic_on)
if po is not None:
generated_cols.append(po)
if self.version_id_col is not None:
generated_cols.append(self.version_id_col)
for c in generated_cols:
if c.key in params and c in self._columntoproperty:
self._set_state_attr_by_column(state, dict_, c, params[c.key])
if postfetch_cols:
_expire_state(state, state.dict,
[self._columntoproperty[c].key
for c in postfetch_cols]
)
# synchronize newly inserted ids from one table to the next
# TODO: this still goes a little too often. would be nice to
# have definitive list of "columns that changed" here
for m, equated_pairs in self._table_to_equated[table]:
sync.populate(state, m, state, m,
equated_pairs,
uowtransaction,
self.passive_updates)
@util.memoized_property
def _table_to_equated(self):
"""memoized map of tables to collections of columns to be
synchronized upwards to the base mapper."""
result = util.defaultdict(list)
for table in self._sorted_tables:
cols = set(table.c)
for m in self.iterate_to_root():
if m._inherits_equated_pairs and \
cols.intersection([l for l, r in m._inherits_equated_pairs]):
result[table].append((m, m._inherits_equated_pairs))
return result
def _delete_obj(self, states, uowtransaction):
"""Issue ``DELETE`` statements for a list of objects.
This is called within the context of a UOWTransaction during a
flush operation.
"""
if 'connection_callable' in uowtransaction.mapper_flush_opts:
connection_callable = \
uowtransaction.mapper_flush_opts['connection_callable']
else:
connection = uowtransaction.transaction.connection(self)
connection_callable = None
tups = []
for state in _sort_states(states):
mapper = _state_mapper(state)
conn = connection_callable and \
connection_callable(self, state.obj()) or \
connection
if 'before_delete' in mapper.extension:
mapper.extension.before_delete(mapper, conn, state.obj())
tups.append((state,
state.dict,
_state_mapper(state),
_state_has_identity(state),
conn))
table_to_mapper = self._sorted_tables
for table in reversed(table_to_mapper.keys()):
delete = util.defaultdict(list)
for state, state_dict, mapper, has_identity, connection in tups:
if not has_identity or table not in mapper._pks_by_table:
continue
params = {}
delete[connection].append(params)
for col in mapper._pks_by_table[table]:
params[col.key] = mapper._get_state_attr_by_column(state, state_dict, col)
if mapper.version_id_col is not None and \
table.c.contains_column(mapper.version_id_col):
params[mapper.version_id_col.key] = \
mapper._get_state_attr_by_column(state, state_dict, mapper.version_id_col)
for connection, del_objects in delete.iteritems():
mapper = table_to_mapper[table]
clause = sql.and_()
for col in mapper._pks_by_table[table]:
clause.clauses.append(col == sql.bindparam(col.key, type_=col.type))
need_version_id = mapper.version_id_col is not None and \
table.c.contains_column(mapper.version_id_col)
if need_version_id:
clause.clauses.append(
mapper.version_id_col ==
sql.bindparam(
mapper.version_id_col.key,
type_=mapper.version_id_col.type
)
)
statement = table.delete(clause)
rows = -1
if need_version_id and \
not connection.dialect.supports_sane_multi_rowcount:
# TODO: need test coverage for this [ticket:1761]
if connection.dialect.supports_sane_rowcount:
rows = 0
# execute deletes individually so that versioned
# rows can be verified
for params in del_objects:
c = connection.execute(statement, params)
rows += c.rowcount
else:
util.warn("Dialect %s does not support deleted rowcount "
"- versioning cannot be verified." %
c.dialect.dialect_description,
stacklevel=12)
connection.execute(statement, del_objects)
else:
c = connection.execute(statement, del_objects)
if connection.dialect.supports_sane_multi_rowcount:
rows = c.rowcount
if rows != -1 and rows != len(del_objects):
raise orm_exc.ConcurrentModificationError(
"Deleted rowcount %d does not match "
"number of objects deleted %d" %
(c.rowcount, len(del_objects))
)
for state, state_dict, mapper, has_identity, connection in tups:
if 'after_delete' in mapper.extension:
mapper.extension.after_delete(mapper, connection, state.obj())
def _instance_processor(self, context, path, adapter,
polymorphic_from=None, extension=None,
only_load_props=None, refresh_state=None,
polymorphic_discriminator=None):
"""Produce a mapper level row processor callable
which processes rows into mapped instances."""
pk_cols = self.primary_key
if polymorphic_from or refresh_state:
polymorphic_on = None
else:
if polymorphic_discriminator is not None:
polymorphic_on = polymorphic_discriminator
else:
polymorphic_on = self.polymorphic_on
polymorphic_instances = util.PopulateDict(
self._configure_subclass_mapper(context, path, adapter)
)
version_id_col = self.version_id_col
if adapter:
pk_cols = [adapter.columns[c] for c in pk_cols]
if polymorphic_on is not None:
polymorphic_on = adapter.columns[polymorphic_on]
if version_id_col is not None:
version_id_col = adapter.columns[version_id_col]
identity_class = self._identity_class
def identity_key(row):
return (identity_class, tuple([row[column] for column in pk_cols]))
new_populators = []
existing_populators = []
load_path = context.query._current_path + path
def populate_state(state, dict_, row, isnew, only_load_props):
if isnew:
if context.propagate_options:
state.load_options = context.propagate_options
if state.load_options:
state.load_path = load_path
if not new_populators:
new_populators[:], existing_populators[:] = \
self._populators(context, path, row, adapter)
if isnew:
populators = new_populators
else:
populators = existing_populators
if only_load_props:
populators = [p for p in populators if p[0] in only_load_props]
for key, populator in populators:
populator(state, dict_, row)
session_identity_map = context.session.identity_map
if not extension:
extension = self.extension
translate_row = extension.get('translate_row', None)
create_instance = extension.get('create_instance', None)
populate_instance = extension.get('populate_instance', None)
append_result = extension.get('append_result', None)
populate_existing = context.populate_existing or self.always_refresh
if self.allow_partial_pks:
is_not_primary_key = _none_set.issuperset
else:
is_not_primary_key = _none_set.issubset
def _instance(row, result):
if translate_row:
ret = translate_row(self, context, row)
if ret is not EXT_CONTINUE:
row = ret
if polymorphic_on is not None:
discriminator = row[polymorphic_on]
if discriminator is not None:
_instance = polymorphic_instances[discriminator]
if _instance:
return _instance(row, result)
# determine identity key
if refresh_state:
identitykey = refresh_state.key
if identitykey is None:
# super-rare condition; a refresh is being called
# on a non-instance-key instance; this is meant to only
# occur within a flush()
identitykey = self._identity_key_from_state(refresh_state)
else:
identitykey = identity_key(row)
instance = session_identity_map.get(identitykey)
if instance is not None:
state = attributes.instance_state(instance)
dict_ = attributes.instance_dict(instance)
isnew = state.runid != context.runid
currentload = not isnew
loaded_instance = False
if not currentload and \
version_id_col is not None and \
context.version_check and \
self._get_state_attr_by_column(
state,
dict_,
self.version_id_col) != row[version_id_col]:
raise orm_exc.ConcurrentModificationError(
"Instance '%s' version of %s does not match %s"
% (state_str(state),
self._get_state_attr_by_column(state, dict_, self.version_id_col),
row[version_id_col]))
elif refresh_state:
# out of band refresh_state detected (i.e. its not in the session.identity_map)
# honor it anyway. this can happen if a _get() occurs within save_obj(), such as
# when eager_defaults is True.
state = refresh_state
instance = state.obj()
dict_ = attributes.instance_dict(instance)
isnew = state.runid != context.runid
currentload = True
loaded_instance = False
else:
# check for non-NULL values in the primary key columns,
# else no entity is returned for the row
if is_not_primary_key(identitykey[1]):
return None
isnew = True
currentload = True
loaded_instance = True
if create_instance:
instance = create_instance(self, context, row, self.class_)
if instance is EXT_CONTINUE:
instance = self.class_manager.new_instance()
else:
manager = attributes.manager_of_class(instance.__class__)
# TODO: if manager is None, raise a friendly error about
# returning instances of unmapped types
manager.setup_instance(instance)
else:
instance = self.class_manager.new_instance()
dict_ = attributes.instance_dict(instance)
state = attributes.instance_state(instance)
state.key = identitykey
# manually adding instance to session. for a complete add,
# session._finalize_loaded() must be called.
state.session_id = context.session.hash_key
session_identity_map.add(state)
if currentload or populate_existing:
if isnew:
state.runid = context.runid
context.progress[state] = dict_
if not populate_instance or \
populate_instance(self, context, row, instance,
only_load_props=only_load_props,
instancekey=identitykey, isnew=isnew) is EXT_CONTINUE:
populate_state(state, dict_, row, isnew, only_load_props)
else:
# populate attributes on non-loading instances which have been expired
# TODO: apply eager loads to un-lazy loaded collections ?
if state in context.partials or state.unloaded:
if state in context.partials:
isnew = False
(d_, attrs) = context.partials[state]
else:
isnew = True
attrs = state.unloaded
# allow query.instances to commit the subset of attrs
context.partials[state] = (dict_, attrs)
if not populate_instance or \
populate_instance(self, context, row, instance,
only_load_props=attrs,
instancekey=identitykey, isnew=isnew) is EXT_CONTINUE:
populate_state(state, dict_, row, isnew, attrs)
if loaded_instance:
state._run_on_load(instance)
if result is not None and \
(not append_result or
append_result(self, context, row, instance,
result, instancekey=identitykey, isnew=isnew)
is EXT_CONTINUE):
result.append(instance)
return instance
return _instance
def _populators(self, context, path, row, adapter):
"""Produce a collection of attribute level row processor callables."""
new_populators, existing_populators = [], []
for prop in self._props.itervalues():
newpop, existingpop = prop.create_row_processor(context, path, self, row, adapter)
if newpop:
new_populators.append((prop.key, newpop))
if existingpop:
existing_populators.append((prop.key, existingpop))
return new_populators, existing_populators
def _configure_subclass_mapper(self, context, path, adapter):
"""Produce a mapper level row processor callable factory for mappers inheriting this one."""
def configure_subclass_mapper(discriminator):
try:
mapper = self.polymorphic_map[discriminator]
except KeyError:
raise AssertionError("No such polymorphic_identity %r is defined" % discriminator)
if mapper is self:
return None
# replace the tip of the path info with the subclass mapper being used.
# that way accurate "load_path" info is available for options
# invoked during deferred loads.
# we lose AliasedClass path elements this way, but currently,
# those are not needed at this stage.
# this asserts to true
#assert mapper.isa(_class_to_mapper(path[-1]))
return mapper._instance_processor(context, path[0:-1] + (mapper,),
adapter, polymorphic_from=self)
return configure_subclass_mapper
log.class_logger(Mapper)
def reconstructor(fn):
"""Decorate a method as the 'reconstructor' hook.
Designates a method as the "reconstructor", an ``__init__``-like
method that will be called by the ORM after the instance has been
loaded from the database or otherwise reconstituted.
The reconstructor will be invoked with no arguments. Scalar
(non-collection) database-mapped attributes of the instance will
be available for use within the function. Eagerly-loaded
collections are generally not yet available and will usually only
contain the first element. ORM state changes made to objects at
this stage will not be recorded for the next flush() operation, so
the activity within a reconstructor should be conservative.
"""
fn.__sa_reconstructor__ = True
return fn
def validates(*names):
"""Decorate a method as a 'validator' for one or more named properties.
Designates a method as a validator, a method which receives the
name of the attribute as well as a value to be assigned, or in the
case of a collection to be added to the collection. The function
can then raise validation exceptions to halt the process from continuing,
or can modify or replace the value before proceeding. The function
should otherwise return the given value.
"""
def wrap(fn):
fn.__sa_validators__ = names
return fn
return wrap
def _event_on_init(state, instance, args, kwargs):
"""Trigger mapper compilation and run init_instance hooks."""
instrumenting_mapper = state.manager.info[_INSTRUMENTOR]
# compile() always compiles all mappers
instrumenting_mapper.compile()
if 'init_instance' in instrumenting_mapper.extension:
instrumenting_mapper.extension.init_instance(
instrumenting_mapper, instrumenting_mapper.class_,
state.manager.events.original_init,
instance, args, kwargs)
def _event_on_init_failure(state, instance, args, kwargs):
"""Run init_failed hooks."""
instrumenting_mapper = state.manager.info[_INSTRUMENTOR]
if 'init_failed' in instrumenting_mapper.extension:
util.warn_exception(
instrumenting_mapper.extension.init_failed,
instrumenting_mapper, instrumenting_mapper.class_,
state.manager.events.original_init, instance, args, kwargs)
def _event_on_resurrect(state, instance):
# re-populate the primary key elements
# of the dict based on the mapping.
instrumenting_mapper = state.manager.info[_INSTRUMENTOR]
for col, val in zip(instrumenting_mapper.primary_key, state.key[1]):
instrumenting_mapper._set_state_attr_by_column(state, state.dict, col, val)
def _sort_states(states):
return sorted(states, key=operator.attrgetter('sort_key'))
def _load_scalar_attributes(state, attribute_names):
"""initiate a column-based attribute refresh operation."""
mapper = _state_mapper(state)
session = _state_session(state)
if not session:
raise orm_exc.DetachedInstanceError("Instance %s is not bound to a Session; "
"attribute refresh operation cannot proceed" % (state_str(state)))
has_key = _state_has_identity(state)
result = False
if mapper.inherits and not mapper.concrete:
statement = mapper._optimized_get_statement(state, attribute_names)
if statement is not None:
result = session.query(mapper).from_statement(statement).\
_get(None,
only_load_props=attribute_names,
refresh_state=state)
if result is False:
if has_key:
identity_key = state.key
else:
identity_key = mapper._identity_key_from_state(state)
result = session.query(mapper)._get(
identity_key,
refresh_state=state,
only_load_props=attribute_names)
# if instance is pending, a refresh operation
# may not complete (even if PK attributes are assigned)
if has_key and result is None:
raise orm_exc.ObjectDeletedError("Instance '%s' has been deleted." % state_str(state))
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