2025 lines
72 KiB
Python
2025 lines
72 KiB
Python
|
# orm/strategies.py
|
||
|
|
# Copyright (C) 2005-2018 the SQLAlchemy authors and contributors
|
||
|
|
# <see AUTHORS file>
|
||
|
|
#
|
||
|
|
# This module is part of SQLAlchemy and is released under
|
||
|
|
# the MIT License: http://www.opensource.org/licenses/mit-license.php
|
||
|
|
|
||
|
|
"""sqlalchemy.orm.interfaces.LoaderStrategy
|
||
|
|
implementations, and related MapperOptions."""
|
||
|
|
|
||
|
|
from .. import exc as sa_exc, inspect
|
||
|
|
from .. import util, log, event
|
||
|
|
from ..sql import util as sql_util, visitors
|
||
|
|
from .. import sql
|
||
|
|
from . import (
|
||
|
|
attributes, interfaces, exc as orm_exc, loading,
|
||
|
|
unitofwork, util as orm_util, query
|
||
|
|
)
|
||
|
|
from .state import InstanceState
|
||
|
|
from .util import _none_set, aliased
|
||
|
|
from . import properties
|
||
|
|
from .interfaces import (
|
||
|
|
LoaderStrategy, StrategizedProperty
|
||
|
|
)
|
||
|
|
from .base import _SET_DEFERRED_EXPIRED, _DEFER_FOR_STATE
|
||
|
|
from .session import _state_session
|
||
|
|
import itertools
|
||
|
|
|
||
|
|
|
||
|
|
def _register_attribute(
|
||
|
|
prop, mapper, useobject,
|
||
|
|
compare_function=None,
|
||
|
|
typecallable=None,
|
||
|
|
callable_=None,
|
||
|
|
proxy_property=None,
|
||
|
|
active_history=False,
|
||
|
|
impl_class=None,
|
||
|
|
**kw
|
||
|
|
):
|
||
|
|
|
||
|
|
attribute_ext = list(util.to_list(prop.extension, default=[]))
|
||
|
|
|
||
|
|
listen_hooks = []
|
||
|
|
|
||
|
|
uselist = useobject and prop.uselist
|
||
|
|
|
||
|
|
if useobject and prop.single_parent:
|
||
|
|
listen_hooks.append(single_parent_validator)
|
||
|
|
|
||
|
|
if prop.key in prop.parent.validators:
|
||
|
|
fn, opts = prop.parent.validators[prop.key]
|
||
|
|
listen_hooks.append(
|
||
|
|
lambda desc, prop: orm_util._validator_events(
|
||
|
|
desc,
|
||
|
|
prop.key, fn, **opts)
|
||
|
|
)
|
||
|
|
|
||
|
|
if useobject:
|
||
|
|
listen_hooks.append(unitofwork.track_cascade_events)
|
||
|
|
|
||
|
|
# need to assemble backref listeners
|
||
|
|
# after the singleparentvalidator, mapper validator
|
||
|
|
if useobject:
|
||
|
|
backref = prop.back_populates
|
||
|
|
if backref:
|
||
|
|
listen_hooks.append(
|
||
|
|
lambda desc, prop: attributes.backref_listeners(
|
||
|
|
desc,
|
||
|
|
backref,
|
||
|
|
uselist
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
# a single MapperProperty is shared down a class inheritance
|
||
|
|
# hierarchy, so we set up attribute instrumentation and backref event
|
||
|
|
# for each mapper down the hierarchy.
|
||
|
|
|
||
|
|
# typically, "mapper" is the same as prop.parent, due to the way
|
||
|
|
# the configure_mappers() process runs, however this is not strongly
|
||
|
|
# enforced, and in the case of a second configure_mappers() run the
|
||
|
|
# mapper here might not be prop.parent; also, a subclass mapper may
|
||
|
|
# be called here before a superclass mapper. That is, can't depend
|
||
|
|
# on mappers not already being set up so we have to check each one.
|
||
|
|
|
||
|
|
for m in mapper.self_and_descendants:
|
||
|
|
if prop is m._props.get(prop.key) and \
|
||
|
|
not m.class_manager._attr_has_impl(prop.key):
|
||
|
|
|
||
|
|
desc = attributes.register_attribute_impl(
|
||
|
|
m.class_,
|
||
|
|
prop.key,
|
||
|
|
parent_token=prop,
|
||
|
|
uselist=uselist,
|
||
|
|
compare_function=compare_function,
|
||
|
|
useobject=useobject,
|
||
|
|
extension=attribute_ext,
|
||
|
|
trackparent=useobject and (
|
||
|
|
prop.single_parent or
|
||
|
|
prop.direction is interfaces.ONETOMANY),
|
||
|
|
typecallable=typecallable,
|
||
|
|
callable_=callable_,
|
||
|
|
active_history=active_history,
|
||
|
|
impl_class=impl_class,
|
||
|
|
send_modified_events=not useobject or not prop.viewonly,
|
||
|
|
doc=prop.doc,
|
||
|
|
**kw
|
||
|
|
)
|
||
|
|
|
||
|
|
for hook in listen_hooks:
|
||
|
|
hook(desc, prop)
|
||
|
|
|
||
|
|
|
||
|
|
@properties.ColumnProperty.strategy_for(instrument=False, deferred=False)
|
||
|
|
class UninstrumentedColumnLoader(LoaderStrategy):
|
||
|
|
"""Represent a non-instrumented MapperProperty.
|
||
|
|
|
||
|
|
The polymorphic_on argument of mapper() often results in this,
|
||
|
|
if the argument is against the with_polymorphic selectable.
|
||
|
|
|
||
|
|
"""
|
||
|
|
__slots__ = 'columns',
|
||
|
|
|
||
|
|
def __init__(self, parent, strategy_key):
|
||
|
|
super(UninstrumentedColumnLoader, self).__init__(parent, strategy_key)
|
||
|
|
self.columns = self.parent_property.columns
|
||
|
|
|
||
|
|
def setup_query(
|
||
|
|
self, context, entity, path, loadopt, adapter,
|
||
|
|
column_collection=None, **kwargs):
|
||
|
|
for c in self.columns:
|
||
|
|
if adapter:
|
||
|
|
c = adapter.columns[c]
|
||
|
|
column_collection.append(c)
|
||
|
|
|
||
|
|
def create_row_processor(
|
||
|
|
self, context, path, loadopt,
|
||
|
|
mapper, result, adapter, populators):
|
||
|
|
pass
|
||
|
|
|
||
|
|
|
||
|
|
@log.class_logger
|
||
|
|
@properties.ColumnProperty.strategy_for(instrument=True, deferred=False)
|
||
|
|
class ColumnLoader(LoaderStrategy):
|
||
|
|
"""Provide loading behavior for a :class:`.ColumnProperty`."""
|
||
|
|
|
||
|
|
__slots__ = 'columns', 'is_composite'
|
||
|
|
|
||
|
|
def __init__(self, parent, strategy_key):
|
||
|
|
super(ColumnLoader, self).__init__(parent, strategy_key)
|
||
|
|
self.columns = self.parent_property.columns
|
||
|
|
self.is_composite = hasattr(self.parent_property, 'composite_class')
|
||
|
|
|
||
|
|
def setup_query(
|
||
|
|
self, context, entity, path, loadopt,
|
||
|
|
adapter, column_collection, memoized_populators, **kwargs):
|
||
|
|
|
||
|
|
for c in self.columns:
|
||
|
|
if adapter:
|
||
|
|
c = adapter.columns[c]
|
||
|
|
column_collection.append(c)
|
||
|
|
|
||
|
|
fetch = self.columns[0]
|
||
|
|
if adapter:
|
||
|
|
fetch = adapter.columns[fetch]
|
||
|
|
memoized_populators[self.parent_property] = fetch
|
||
|
|
|
||
|
|
def init_class_attribute(self, mapper):
|
||
|
|
self.is_class_level = True
|
||
|
|
coltype = self.columns[0].type
|
||
|
|
# TODO: check all columns ? check for foreign key as well?
|
||
|
|
active_history = self.parent_property.active_history or \
|
||
|
|
self.columns[0].primary_key or \
|
||
|
|
mapper.version_id_col in set(self.columns)
|
||
|
|
|
||
|
|
_register_attribute(
|
||
|
|
self.parent_property, mapper, useobject=False,
|
||
|
|
compare_function=coltype.compare_values,
|
||
|
|
active_history=active_history
|
||
|
|
)
|
||
|
|
|
||
|
|
def create_row_processor(
|
||
|
|
self, context, path,
|
||
|
|
loadopt, mapper, result, adapter, populators):
|
||
|
|
# look through list of columns represented here
|
||
|
|
# to see which, if any, is present in the row.
|
||
|
|
for col in self.columns:
|
||
|
|
if adapter:
|
||
|
|
col = adapter.columns[col]
|
||
|
|
getter = result._getter(col, False)
|
||
|
|
if getter:
|
||
|
|
populators["quick"].append((self.key, getter))
|
||
|
|
break
|
||
|
|
else:
|
||
|
|
populators["expire"].append((self.key, True))
|
||
|
|
|
||
|
|
|
||
|
|
@log.class_logger
|
||
|
|
@properties.ColumnProperty.strategy_for(query_expression=True)
|
||
|
|
class ExpressionColumnLoader(ColumnLoader):
|
||
|
|
def __init__(self, parent, strategy_key):
|
||
|
|
super(ExpressionColumnLoader, self).__init__(parent, strategy_key)
|
||
|
|
|
||
|
|
def setup_query(
|
||
|
|
self, context, entity, path, loadopt,
|
||
|
|
adapter, column_collection, memoized_populators, **kwargs):
|
||
|
|
|
||
|
|
if loadopt and "expression" in loadopt.local_opts:
|
||
|
|
columns = [loadopt.local_opts["expression"]]
|
||
|
|
|
||
|
|
for c in columns:
|
||
|
|
if adapter:
|
||
|
|
c = adapter.columns[c]
|
||
|
|
column_collection.append(c)
|
||
|
|
|
||
|
|
fetch = columns[0]
|
||
|
|
if adapter:
|
||
|
|
fetch = adapter.columns[fetch]
|
||
|
|
memoized_populators[self.parent_property] = fetch
|
||
|
|
|
||
|
|
def create_row_processor(
|
||
|
|
self, context, path,
|
||
|
|
loadopt, mapper, result, adapter, populators):
|
||
|
|
# look through list of columns represented here
|
||
|
|
# to see which, if any, is present in the row.
|
||
|
|
if loadopt and "expression" in loadopt.local_opts:
|
||
|
|
columns = [loadopt.local_opts["expression"]]
|
||
|
|
|
||
|
|
for col in columns:
|
||
|
|
if adapter:
|
||
|
|
col = adapter.columns[col]
|
||
|
|
getter = result._getter(col, False)
|
||
|
|
if getter:
|
||
|
|
populators["quick"].append((self.key, getter))
|
||
|
|
break
|
||
|
|
else:
|
||
|
|
populators["expire"].append((self.key, True))
|
||
|
|
|
||
|
|
def init_class_attribute(self, mapper):
|
||
|
|
self.is_class_level = True
|
||
|
|
|
||
|
|
_register_attribute(
|
||
|
|
self.parent_property, mapper, useobject=False,
|
||
|
|
compare_function=self.columns[0].type.compare_values,
|
||
|
|
accepts_scalar_loader=False
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
@log.class_logger
|
||
|
|
@properties.ColumnProperty.strategy_for(deferred=True, instrument=True)
|
||
|
|
@properties.ColumnProperty.strategy_for(do_nothing=True)
|
||
|
|
class DeferredColumnLoader(LoaderStrategy):
|
||
|
|
"""Provide loading behavior for a deferred :class:`.ColumnProperty`."""
|
||
|
|
|
||
|
|
__slots__ = 'columns', 'group'
|
||
|
|
|
||
|
|
def __init__(self, parent, strategy_key):
|
||
|
|
super(DeferredColumnLoader, self).__init__(parent, strategy_key)
|
||
|
|
if hasattr(self.parent_property, 'composite_class'):
|
||
|
|
raise NotImplementedError("Deferred loading for composite "
|
||
|
|
"types not implemented yet")
|
||
|
|
self.columns = self.parent_property.columns
|
||
|
|
self.group = self.parent_property.group
|
||
|
|
|
||
|
|
def create_row_processor(
|
||
|
|
self, context, path, loadopt,
|
||
|
|
mapper, result, adapter, populators):
|
||
|
|
|
||
|
|
# this path currently does not check the result
|
||
|
|
# for the column; this is because in most cases we are
|
||
|
|
# working just with the setup_query() directive which does
|
||
|
|
# not support this, and the behavior here should be consistent.
|
||
|
|
if not self.is_class_level:
|
||
|
|
set_deferred_for_local_state = \
|
||
|
|
self.parent_property._deferred_column_loader
|
||
|
|
populators["new"].append((self.key, set_deferred_for_local_state))
|
||
|
|
else:
|
||
|
|
populators["expire"].append((self.key, False))
|
||
|
|
|
||
|
|
def init_class_attribute(self, mapper):
|
||
|
|
self.is_class_level = True
|
||
|
|
|
||
|
|
_register_attribute(
|
||
|
|
self.parent_property, mapper, useobject=False,
|
||
|
|
compare_function=self.columns[0].type.compare_values,
|
||
|
|
callable_=self._load_for_state,
|
||
|
|
expire_missing=False
|
||
|
|
)
|
||
|
|
|
||
|
|
def setup_query(
|
||
|
|
self, context, entity, path, loadopt,
|
||
|
|
adapter, column_collection, memoized_populators,
|
||
|
|
only_load_props=None, **kw):
|
||
|
|
|
||
|
|
if (
|
||
|
|
(
|
||
|
|
loadopt and
|
||
|
|
'undefer_pks' in loadopt.local_opts and
|
||
|
|
set(self.columns).intersection(
|
||
|
|
self.parent._should_undefer_in_wildcard)
|
||
|
|
)
|
||
|
|
or
|
||
|
|
(
|
||
|
|
loadopt and
|
||
|
|
self.group and
|
||
|
|
loadopt.local_opts.get('undefer_group_%s' % self.group, False)
|
||
|
|
)
|
||
|
|
or
|
||
|
|
(
|
||
|
|
only_load_props and self.key in only_load_props
|
||
|
|
)
|
||
|
|
):
|
||
|
|
self.parent_property._get_strategy(
|
||
|
|
(("deferred", False), ("instrument", True))
|
||
|
|
).setup_query(
|
||
|
|
context, entity,
|
||
|
|
path, loadopt, adapter,
|
||
|
|
column_collection, memoized_populators, **kw)
|
||
|
|
elif self.is_class_level:
|
||
|
|
memoized_populators[self.parent_property] = _SET_DEFERRED_EXPIRED
|
||
|
|
else:
|
||
|
|
memoized_populators[self.parent_property] = _DEFER_FOR_STATE
|
||
|
|
|
||
|
|
def _load_for_state(self, state, passive):
|
||
|
|
if not state.key:
|
||
|
|
return attributes.ATTR_EMPTY
|
||
|
|
|
||
|
|
if not passive & attributes.SQL_OK:
|
||
|
|
return attributes.PASSIVE_NO_RESULT
|
||
|
|
|
||
|
|
localparent = state.manager.mapper
|
||
|
|
|
||
|
|
if self.group:
|
||
|
|
toload = [
|
||
|
|
p.key for p in
|
||
|
|
localparent.iterate_properties
|
||
|
|
if isinstance(p, StrategizedProperty) and
|
||
|
|
isinstance(p.strategy, DeferredColumnLoader) and
|
||
|
|
p.group == self.group
|
||
|
|
]
|
||
|
|
else:
|
||
|
|
toload = [self.key]
|
||
|
|
|
||
|
|
# narrow the keys down to just those which have no history
|
||
|
|
group = [k for k in toload if k in state.unmodified]
|
||
|
|
|
||
|
|
session = _state_session(state)
|
||
|
|
if session is None:
|
||
|
|
raise orm_exc.DetachedInstanceError(
|
||
|
|
"Parent instance %s is not bound to a Session; "
|
||
|
|
"deferred load operation of attribute '%s' cannot proceed" %
|
||
|
|
(orm_util.state_str(state), self.key)
|
||
|
|
)
|
||
|
|
|
||
|
|
query = session.query(localparent)
|
||
|
|
if loading.load_on_ident(
|
||
|
|
query, state.key,
|
||
|
|
only_load_props=group, refresh_state=state) is None:
|
||
|
|
raise orm_exc.ObjectDeletedError(state)
|
||
|
|
|
||
|
|
return attributes.ATTR_WAS_SET
|
||
|
|
|
||
|
|
|
||
|
|
class LoadDeferredColumns(object):
|
||
|
|
"""serializable loader object used by DeferredColumnLoader"""
|
||
|
|
|
||
|
|
def __init__(self, key):
|
||
|
|
self.key = key
|
||
|
|
|
||
|
|
def __call__(self, state, passive=attributes.PASSIVE_OFF):
|
||
|
|
key = self.key
|
||
|
|
|
||
|
|
localparent = state.manager.mapper
|
||
|
|
prop = localparent._props[key]
|
||
|
|
strategy = prop._strategies[DeferredColumnLoader]
|
||
|
|
return strategy._load_for_state(state, passive)
|
||
|
|
|
||
|
|
|
||
|
|
class AbstractRelationshipLoader(LoaderStrategy):
|
||
|
|
"""LoaderStratgies which deal with related objects."""
|
||
|
|
|
||
|
|
__slots__ = 'mapper', 'target', 'uselist'
|
||
|
|
|
||
|
|
def __init__(self, parent, strategy_key):
|
||
|
|
super(AbstractRelationshipLoader, self).__init__(parent, strategy_key)
|
||
|
|
self.mapper = self.parent_property.mapper
|
||
|
|
self.target = self.parent_property.target
|
||
|
|
self.uselist = self.parent_property.uselist
|
||
|
|
|
||
|
|
|
||
|
|
@log.class_logger
|
||
|
|
@properties.RelationshipProperty.strategy_for(do_nothing=True)
|
||
|
|
class DoNothingLoader(LoaderStrategy):
|
||
|
|
"""Relationship loader that makes no change to the object's state.
|
||
|
|
|
||
|
|
Compared to NoLoader, this loader does not initialize the
|
||
|
|
collection/attribute to empty/none; the usual default LazyLoader will
|
||
|
|
take effect.
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
|
||
|
|
@log.class_logger
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy="noload")
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy=None)
|
||
|
|
class NoLoader(AbstractRelationshipLoader):
|
||
|
|
"""Provide loading behavior for a :class:`.RelationshipProperty`
|
||
|
|
with "lazy=None".
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
__slots__ = ()
|
||
|
|
|
||
|
|
def init_class_attribute(self, mapper):
|
||
|
|
self.is_class_level = True
|
||
|
|
|
||
|
|
_register_attribute(
|
||
|
|
self.parent_property, mapper,
|
||
|
|
useobject=True,
|
||
|
|
typecallable=self.parent_property.collection_class,
|
||
|
|
)
|
||
|
|
|
||
|
|
def create_row_processor(
|
||
|
|
self, context, path, loadopt, mapper,
|
||
|
|
result, adapter, populators):
|
||
|
|
def invoke_no_load(state, dict_, row):
|
||
|
|
if self.uselist:
|
||
|
|
state.manager.get_impl(self.key).initialize(state, dict_)
|
||
|
|
else:
|
||
|
|
dict_[self.key] = None
|
||
|
|
populators["new"].append((self.key, invoke_no_load))
|
||
|
|
|
||
|
|
|
||
|
|
@log.class_logger
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy=True)
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy="select")
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy="raise")
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy="raise_on_sql")
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy="baked_select")
|
||
|
|
class LazyLoader(AbstractRelationshipLoader, util.MemoizedSlots):
|
||
|
|
"""Provide loading behavior for a :class:`.RelationshipProperty`
|
||
|
|
with "lazy=True", that is loads when first accessed.
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
__slots__ = (
|
||
|
|
'_lazywhere', '_rev_lazywhere', 'use_get', '_bind_to_col',
|
||
|
|
'_equated_columns', '_rev_bind_to_col', '_rev_equated_columns',
|
||
|
|
'_simple_lazy_clause', '_raise_always', '_raise_on_sql',
|
||
|
|
'_bakery')
|
||
|
|
|
||
|
|
def __init__(self, parent, strategy_key):
|
||
|
|
super(LazyLoader, self).__init__(parent, strategy_key)
|
||
|
|
self._raise_always = self.strategy_opts["lazy"] == "raise"
|
||
|
|
self._raise_on_sql = self.strategy_opts["lazy"] == "raise_on_sql"
|
||
|
|
|
||
|
|
join_condition = self.parent_property._join_condition
|
||
|
|
self._lazywhere, \
|
||
|
|
self._bind_to_col, \
|
||
|
|
self._equated_columns = join_condition.create_lazy_clause()
|
||
|
|
|
||
|
|
self._rev_lazywhere, \
|
||
|
|
self._rev_bind_to_col, \
|
||
|
|
self._rev_equated_columns = join_condition.create_lazy_clause(
|
||
|
|
reverse_direction=True)
|
||
|
|
|
||
|
|
self.logger.info("%s lazy loading clause %s", self, self._lazywhere)
|
||
|
|
|
||
|
|
# determine if our "lazywhere" clause is the same as the mapper's
|
||
|
|
# get() clause. then we can just use mapper.get()
|
||
|
|
self.use_get = not self.uselist and \
|
||
|
|
self.mapper._get_clause[0].compare(
|
||
|
|
self._lazywhere,
|
||
|
|
use_proxies=True,
|
||
|
|
equivalents=self.mapper._equivalent_columns
|
||
|
|
)
|
||
|
|
|
||
|
|
if self.use_get:
|
||
|
|
for col in list(self._equated_columns):
|
||
|
|
if col in self.mapper._equivalent_columns:
|
||
|
|
for c in self.mapper._equivalent_columns[col]:
|
||
|
|
self._equated_columns[c] = self._equated_columns[col]
|
||
|
|
|
||
|
|
self.logger.info("%s will use query.get() to "
|
||
|
|
"optimize instance loads", self)
|
||
|
|
|
||
|
|
def init_class_attribute(self, mapper):
|
||
|
|
self.is_class_level = True
|
||
|
|
|
||
|
|
active_history = (
|
||
|
|
self.parent_property.active_history or
|
||
|
|
self.parent_property.direction is not interfaces.MANYTOONE or
|
||
|
|
not self.use_get
|
||
|
|
)
|
||
|
|
|
||
|
|
# MANYTOONE currently only needs the
|
||
|
|
# "old" value for delete-orphan
|
||
|
|
# cascades. the required _SingleParentValidator
|
||
|
|
# will enable active_history
|
||
|
|
# in that case. otherwise we don't need the
|
||
|
|
# "old" value during backref operations.
|
||
|
|
_register_attribute(
|
||
|
|
self.parent_property,
|
||
|
|
mapper,
|
||
|
|
useobject=True,
|
||
|
|
callable_=self._load_for_state,
|
||
|
|
typecallable=self.parent_property.collection_class,
|
||
|
|
active_history=active_history
|
||
|
|
)
|
||
|
|
|
||
|
|
def _memoized_attr__simple_lazy_clause(self):
|
||
|
|
criterion, bind_to_col = (
|
||
|
|
self._lazywhere,
|
||
|
|
self._bind_to_col
|
||
|
|
)
|
||
|
|
|
||
|
|
params = []
|
||
|
|
|
||
|
|
def visit_bindparam(bindparam):
|
||
|
|
bindparam.unique = False
|
||
|
|
if bindparam._identifying_key in bind_to_col:
|
||
|
|
params.append((
|
||
|
|
bindparam.key, bind_to_col[bindparam._identifying_key],
|
||
|
|
None))
|
||
|
|
elif bindparam.callable is None:
|
||
|
|
params.append((bindparam.key, None, bindparam.value))
|
||
|
|
|
||
|
|
criterion = visitors.cloned_traverse(
|
||
|
|
criterion, {}, {'bindparam': visit_bindparam}
|
||
|
|
)
|
||
|
|
|
||
|
|
return criterion, params
|
||
|
|
|
||
|
|
def _generate_lazy_clause(self, state, passive):
|
||
|
|
criterion, param_keys = self._simple_lazy_clause
|
||
|
|
|
||
|
|
if state is None:
|
||
|
|
return sql_util.adapt_criterion_to_null(
|
||
|
|
criterion, [key for key, ident, value in param_keys])
|
||
|
|
|
||
|
|
mapper = self.parent_property.parent
|
||
|
|
|
||
|
|
o = state.obj() # strong ref
|
||
|
|
dict_ = attributes.instance_dict(o)
|
||
|
|
|
||
|
|
if passive & attributes.INIT_OK:
|
||
|
|
passive ^= attributes.INIT_OK
|
||
|
|
|
||
|
|
params = {}
|
||
|
|
for key, ident, value in param_keys:
|
||
|
|
if ident is not None:
|
||
|
|
if passive and passive & attributes.LOAD_AGAINST_COMMITTED:
|
||
|
|
value = mapper._get_committed_state_attr_by_column(
|
||
|
|
state, dict_, ident, passive)
|
||
|
|
else:
|
||
|
|
value = mapper._get_state_attr_by_column(
|
||
|
|
state, dict_, ident, passive)
|
||
|
|
|
||
|
|
params[key] = value
|
||
|
|
|
||
|
|
return criterion, params
|
||
|
|
|
||
|
|
def _invoke_raise_load(self, state, passive, lazy):
|
||
|
|
raise sa_exc.InvalidRequestError(
|
||
|
|
"'%s' is not available due to lazy='%s'" % (self, lazy)
|
||
|
|
)
|
||
|
|
|
||
|
|
def _load_for_state(self, state, passive):
|
||
|
|
|
||
|
|
if not state.key and (
|
||
|
|
(
|
||
|
|
not self.parent_property.load_on_pending
|
||
|
|
and not state._load_pending
|
||
|
|
)
|
||
|
|
or not state.session_id
|
||
|
|
):
|
||
|
|
return attributes.ATTR_EMPTY
|
||
|
|
|
||
|
|
pending = not state.key
|
||
|
|
primary_key_identity = None
|
||
|
|
|
||
|
|
if (
|
||
|
|
(not passive & attributes.SQL_OK and not self.use_get)
|
||
|
|
or
|
||
|
|
(not passive & attributes.NON_PERSISTENT_OK and pending)
|
||
|
|
):
|
||
|
|
return attributes.PASSIVE_NO_RESULT
|
||
|
|
|
||
|
|
if self._raise_always:
|
||
|
|
self._invoke_raise_load(state, passive, "raise")
|
||
|
|
|
||
|
|
session = _state_session(state)
|
||
|
|
if not session:
|
||
|
|
raise orm_exc.DetachedInstanceError(
|
||
|
|
"Parent instance %s is not bound to a Session; "
|
||
|
|
"lazy load operation of attribute '%s' cannot proceed" %
|
||
|
|
(orm_util.state_str(state), self.key)
|
||
|
|
)
|
||
|
|
|
||
|
|
# if we have a simple primary key load, check the
|
||
|
|
# identity map without generating a Query at all
|
||
|
|
if self.use_get:
|
||
|
|
primary_key_identity = self._get_ident_for_use_get(
|
||
|
|
session,
|
||
|
|
state,
|
||
|
|
passive
|
||
|
|
)
|
||
|
|
if attributes.PASSIVE_NO_RESULT in primary_key_identity:
|
||
|
|
return attributes.PASSIVE_NO_RESULT
|
||
|
|
elif attributes.NEVER_SET in primary_key_identity:
|
||
|
|
return attributes.NEVER_SET
|
||
|
|
|
||
|
|
if _none_set.issuperset(primary_key_identity):
|
||
|
|
return None
|
||
|
|
|
||
|
|
# look for this identity in the identity map. Delegate to the
|
||
|
|
# Query class in use, as it may have special rules for how it
|
||
|
|
# does this, including how it decides what the correct
|
||
|
|
# identity_token would be for this identity
|
||
|
|
instance = session._query_cls._identity_lookup(
|
||
|
|
session, self.mapper, primary_key_identity,
|
||
|
|
passive=passive
|
||
|
|
)
|
||
|
|
|
||
|
|
if instance is not None:
|
||
|
|
return instance
|
||
|
|
elif not passive & attributes.SQL_OK or \
|
||
|
|
not passive & attributes.RELATED_OBJECT_OK:
|
||
|
|
return attributes.PASSIVE_NO_RESULT
|
||
|
|
|
||
|
|
return self._emit_lazyload(
|
||
|
|
session, state, primary_key_identity, passive)
|
||
|
|
|
||
|
|
def _get_ident_for_use_get(self, session, state, passive):
|
||
|
|
instance_mapper = state.manager.mapper
|
||
|
|
|
||
|
|
if passive & attributes.LOAD_AGAINST_COMMITTED:
|
||
|
|
get_attr = instance_mapper._get_committed_state_attr_by_column
|
||
|
|
else:
|
||
|
|
get_attr = instance_mapper._get_state_attr_by_column
|
||
|
|
|
||
|
|
dict_ = state.dict
|
||
|
|
|
||
|
|
return [
|
||
|
|
get_attr(
|
||
|
|
state,
|
||
|
|
dict_,
|
||
|
|
self._equated_columns[pk],
|
||
|
|
passive=passive)
|
||
|
|
for pk in self.mapper.primary_key
|
||
|
|
]
|
||
|
|
|
||
|
|
@util.dependencies("sqlalchemy.ext.baked")
|
||
|
|
def _memoized_attr__bakery(self, baked):
|
||
|
|
return baked.bakery(size=50)
|
||
|
|
|
||
|
|
@util.dependencies(
|
||
|
|
"sqlalchemy.orm.strategy_options")
|
||
|
|
def _emit_lazyload(
|
||
|
|
self, strategy_options, session, state,
|
||
|
|
primary_key_identity, passive):
|
||
|
|
# emit lazy load now using BakedQuery, to cut way down on the overhead
|
||
|
|
# of generating queries.
|
||
|
|
# there are two big things we are trying to guard against here:
|
||
|
|
#
|
||
|
|
# 1. two different lazy loads that need to have a different result,
|
||
|
|
# being cached on the same key. The results between two lazy loads
|
||
|
|
# can be different due to the options passed to the query, which
|
||
|
|
# take effect for descendant objects. Therefore we have to make
|
||
|
|
# sure paths and load options generate good cache keys, and if they
|
||
|
|
# don't, we don't cache.
|
||
|
|
# 2. a lazy load that gets cached on a key that includes some
|
||
|
|
# "throwaway" object, like a per-query AliasedClass, meaning
|
||
|
|
# the cache key will never be seen again and the cache itself
|
||
|
|
# will fill up. (the cache is an LRU cache, so while we won't
|
||
|
|
# run out of memory, it will perform terribly when it's full. A
|
||
|
|
# warning is emitted if this occurs.) We must prevent the
|
||
|
|
# generation of a cache key that is including a throwaway object
|
||
|
|
# in the key.
|
||
|
|
|
||
|
|
# note that "lazy='select'" and "lazy=True" make two separate
|
||
|
|
# lazy loaders. Currently the LRU cache is local to the LazyLoader,
|
||
|
|
# however add ourselves to the initial cache key just to future
|
||
|
|
# proof in case it moves
|
||
|
|
q = self._bakery(lambda session: session.query(self.mapper), self)
|
||
|
|
|
||
|
|
q.add_criteria(
|
||
|
|
lambda q: q._adapt_all_clauses()._with_invoke_all_eagers(False),
|
||
|
|
self.parent_property)
|
||
|
|
|
||
|
|
if not self.parent_property.bake_queries:
|
||
|
|
q.spoil(full=True)
|
||
|
|
|
||
|
|
if self.parent_property.secondary is not None:
|
||
|
|
q.add_criteria(
|
||
|
|
lambda q:
|
||
|
|
q.select_from(self.mapper, self.parent_property.secondary))
|
||
|
|
|
||
|
|
pending = not state.key
|
||
|
|
|
||
|
|
# don't autoflush on pending
|
||
|
|
if pending or passive & attributes.NO_AUTOFLUSH:
|
||
|
|
q.add_criteria(lambda q: q.autoflush(False))
|
||
|
|
|
||
|
|
if state.load_options:
|
||
|
|
# here, if any of the options cannot return a cache key,
|
||
|
|
# the BakedQuery "spoils" and caching will not occur. a path
|
||
|
|
# that features Cls.attribute.of_type(some_alias) will cancel
|
||
|
|
# caching, for example, since "some_alias" is user-defined and
|
||
|
|
# is usually a throwaway object.
|
||
|
|
effective_path = state.load_path[self.parent_property]
|
||
|
|
q._add_lazyload_options(
|
||
|
|
state.load_options, effective_path
|
||
|
|
)
|
||
|
|
|
||
|
|
if self.use_get:
|
||
|
|
if self._raise_on_sql:
|
||
|
|
self._invoke_raise_load(state, passive, "raise_on_sql")
|
||
|
|
return q(session)._load_on_pk_identity(
|
||
|
|
session.query(self.mapper), primary_key_identity)
|
||
|
|
|
||
|
|
if self.parent_property.order_by:
|
||
|
|
q.add_criteria(
|
||
|
|
lambda q:
|
||
|
|
q.order_by(*util.to_list(self.parent_property.order_by)))
|
||
|
|
|
||
|
|
for rev in self.parent_property._reverse_property:
|
||
|
|
# reverse props that are MANYTOONE are loading *this*
|
||
|
|
# object from get(), so don't need to eager out to those.
|
||
|
|
if rev.direction is interfaces.MANYTOONE and \
|
||
|
|
rev._use_get and \
|
||
|
|
not isinstance(rev.strategy, LazyLoader):
|
||
|
|
|
||
|
|
q.add_criteria(
|
||
|
|
lambda q:
|
||
|
|
q.options(
|
||
|
|
strategy_options.Load.for_existing_path(
|
||
|
|
q._current_path[rev.parent]
|
||
|
|
).lazyload(rev.key)
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
lazy_clause, params = self._generate_lazy_clause(state, passive)
|
||
|
|
|
||
|
|
if pending:
|
||
|
|
if util.has_intersection(
|
||
|
|
orm_util._none_set, params.values()):
|
||
|
|
return None
|
||
|
|
|
||
|
|
elif util.has_intersection(orm_util._never_set, params.values()):
|
||
|
|
return None
|
||
|
|
|
||
|
|
if self._raise_on_sql:
|
||
|
|
self._invoke_raise_load(state, passive, "raise_on_sql")
|
||
|
|
|
||
|
|
q.add_criteria(lambda q: q.filter(lazy_clause))
|
||
|
|
result = q(session).params(**params).all()
|
||
|
|
if self.uselist:
|
||
|
|
return result
|
||
|
|
else:
|
||
|
|
l = len(result)
|
||
|
|
if l:
|
||
|
|
if l > 1:
|
||
|
|
util.warn(
|
||
|
|
"Multiple rows returned with "
|
||
|
|
"uselist=False for lazily-loaded attribute '%s' "
|
||
|
|
% self.parent_property)
|
||
|
|
|
||
|
|
return result[0]
|
||
|
|
else:
|
||
|
|
return None
|
||
|
|
|
||
|
|
def create_row_processor(
|
||
|
|
self, context, path, loadopt,
|
||
|
|
mapper, result, adapter, populators):
|
||
|
|
key = self.key
|
||
|
|
|
||
|
|
if not self.is_class_level:
|
||
|
|
# we are not the primary manager for this attribute
|
||
|
|
# on this class - set up a
|
||
|
|
# per-instance lazyloader, which will override the
|
||
|
|
# class-level behavior.
|
||
|
|
# this currently only happens when using a
|
||
|
|
# "lazyload" option on a "no load"
|
||
|
|
# attribute - "eager" attributes always have a
|
||
|
|
# class-level lazyloader installed.
|
||
|
|
set_lazy_callable = InstanceState._instance_level_callable_processor(
|
||
|
|
mapper.class_manager,
|
||
|
|
LoadLazyAttribute(key, self), key)
|
||
|
|
|
||
|
|
populators["new"].append((self.key, set_lazy_callable))
|
||
|
|
elif context.populate_existing or mapper.always_refresh:
|
||
|
|
def reset_for_lazy_callable(state, dict_, row):
|
||
|
|
# we are the primary manager for this attribute on
|
||
|
|
# this class - reset its
|
||
|
|
# per-instance attribute state, so that the class-level
|
||
|
|
# lazy loader is
|
||
|
|
# executed when next referenced on this instance.
|
||
|
|
# this is needed in
|
||
|
|
# populate_existing() types of scenarios to reset
|
||
|
|
# any existing state.
|
||
|
|
state._reset(dict_, key)
|
||
|
|
|
||
|
|
populators["new"].append((self.key, reset_for_lazy_callable))
|
||
|
|
|
||
|
|
|
||
|
|
class LoadLazyAttribute(object):
|
||
|
|
"""serializable loader object used by LazyLoader"""
|
||
|
|
|
||
|
|
def __init__(self, key, initiating_strategy):
|
||
|
|
self.key = key
|
||
|
|
self.strategy_key = initiating_strategy.strategy_key
|
||
|
|
|
||
|
|
def __call__(self, state, passive=attributes.PASSIVE_OFF):
|
||
|
|
key = self.key
|
||
|
|
instance_mapper = state.manager.mapper
|
||
|
|
prop = instance_mapper._props[key]
|
||
|
|
strategy = prop._strategies[self.strategy_key]
|
||
|
|
|
||
|
|
return strategy._load_for_state(state, passive)
|
||
|
|
|
||
|
|
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy="immediate")
|
||
|
|
class ImmediateLoader(AbstractRelationshipLoader):
|
||
|
|
__slots__ = ()
|
||
|
|
|
||
|
|
def init_class_attribute(self, mapper):
|
||
|
|
self.parent_property.\
|
||
|
|
_get_strategy((("lazy", "select"),)).\
|
||
|
|
init_class_attribute(mapper)
|
||
|
|
|
||
|
|
def setup_query(
|
||
|
|
self, context, entity,
|
||
|
|
path, loadopt, adapter, column_collection=None,
|
||
|
|
parentmapper=None, **kwargs):
|
||
|
|
pass
|
||
|
|
|
||
|
|
def create_row_processor(
|
||
|
|
self, context, path, loadopt,
|
||
|
|
mapper, result, adapter, populators):
|
||
|
|
def load_immediate(state, dict_, row):
|
||
|
|
state.get_impl(self.key).get(state, dict_)
|
||
|
|
|
||
|
|
populators["delayed"].append((self.key, load_immediate))
|
||
|
|
|
||
|
|
|
||
|
|
@log.class_logger
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy="subquery")
|
||
|
|
class SubqueryLoader(AbstractRelationshipLoader):
|
||
|
|
__slots__ = 'join_depth',
|
||
|
|
|
||
|
|
def __init__(self, parent, strategy_key):
|
||
|
|
super(SubqueryLoader, self).__init__(parent, strategy_key)
|
||
|
|
self.join_depth = self.parent_property.join_depth
|
||
|
|
|
||
|
|
def init_class_attribute(self, mapper):
|
||
|
|
self.parent_property.\
|
||
|
|
_get_strategy((("lazy", "select"),)).\
|
||
|
|
init_class_attribute(mapper)
|
||
|
|
|
||
|
|
def setup_query(
|
||
|
|
self, context, entity,
|
||
|
|
path, loadopt, adapter,
|
||
|
|
column_collection=None,
|
||
|
|
parentmapper=None, **kwargs):
|
||
|
|
|
||
|
|
if not context.query._enable_eagerloads:
|
||
|
|
return
|
||
|
|
elif context.query._yield_per:
|
||
|
|
context.query._no_yield_per("subquery")
|
||
|
|
|
||
|
|
path = path[self.parent_property]
|
||
|
|
|
||
|
|
# build up a path indicating the path from the leftmost
|
||
|
|
# entity to the thing we're subquery loading.
|
||
|
|
with_poly_info = path.get(
|
||
|
|
context.attributes,
|
||
|
|
"path_with_polymorphic", None)
|
||
|
|
if with_poly_info is not None:
|
||
|
|
effective_entity = with_poly_info.entity
|
||
|
|
else:
|
||
|
|
effective_entity = self.mapper
|
||
|
|
|
||
|
|
subq_path = context.attributes.get(
|
||
|
|
('subquery_path', None),
|
||
|
|
orm_util.PathRegistry.root)
|
||
|
|
|
||
|
|
subq_path = subq_path + path
|
||
|
|
|
||
|
|
# if not via query option, check for
|
||
|
|
# a cycle
|
||
|
|
if not path.contains(context.attributes, "loader"):
|
||
|
|
if self.join_depth:
|
||
|
|
if (
|
||
|
|
(context.query._current_path.length
|
||
|
|
if context.query._current_path else 0) +
|
||
|
|
path.length
|
||
|
|
) / 2 > self.join_depth:
|
||
|
|
return
|
||
|
|
elif subq_path.contains_mapper(self.mapper):
|
||
|
|
return
|
||
|
|
|
||
|
|
leftmost_mapper, leftmost_attr, leftmost_relationship = \
|
||
|
|
self._get_leftmost(subq_path)
|
||
|
|
|
||
|
|
orig_query = context.attributes.get(
|
||
|
|
("orig_query", SubqueryLoader),
|
||
|
|
context.query)
|
||
|
|
|
||
|
|
# generate a new Query from the original, then
|
||
|
|
# produce a subquery from it.
|
||
|
|
left_alias = self._generate_from_original_query(
|
||
|
|
orig_query, leftmost_mapper,
|
||
|
|
leftmost_attr, leftmost_relationship,
|
||
|
|
entity.entity_zero
|
||
|
|
)
|
||
|
|
|
||
|
|
# generate another Query that will join the
|
||
|
|
# left alias to the target relationships.
|
||
|
|
# basically doing a longhand
|
||
|
|
# "from_self()". (from_self() itself not quite industrial
|
||
|
|
# strength enough for all contingencies...but very close)
|
||
|
|
q = orig_query.session.query(effective_entity)
|
||
|
|
q._attributes = {
|
||
|
|
("orig_query", SubqueryLoader): orig_query,
|
||
|
|
('subquery_path', None): subq_path
|
||
|
|
}
|
||
|
|
|
||
|
|
q = q._set_enable_single_crit(False)
|
||
|
|
to_join, local_attr, parent_alias = \
|
||
|
|
self._prep_for_joins(left_alias, subq_path)
|
||
|
|
q = q.order_by(*local_attr)
|
||
|
|
q = q.add_columns(*local_attr)
|
||
|
|
q = self._apply_joins(
|
||
|
|
q, to_join, left_alias,
|
||
|
|
parent_alias, effective_entity)
|
||
|
|
|
||
|
|
q = self._setup_options(q, subq_path, orig_query, effective_entity)
|
||
|
|
q = self._setup_outermost_orderby(q)
|
||
|
|
|
||
|
|
# add new query to attributes to be picked up
|
||
|
|
# by create_row_processor
|
||
|
|
path.set(context.attributes, "subquery", q)
|
||
|
|
|
||
|
|
def _get_leftmost(self, subq_path):
|
||
|
|
subq_path = subq_path.path
|
||
|
|
subq_mapper = orm_util._class_to_mapper(subq_path[0])
|
||
|
|
|
||
|
|
# determine attributes of the leftmost mapper
|
||
|
|
if self.parent.isa(subq_mapper) and \
|
||
|
|
self.parent_property is subq_path[1]:
|
||
|
|
leftmost_mapper, leftmost_prop = \
|
||
|
|
self.parent, self.parent_property
|
||
|
|
else:
|
||
|
|
leftmost_mapper, leftmost_prop = \
|
||
|
|
subq_mapper, \
|
||
|
|
subq_path[1]
|
||
|
|
|
||
|
|
leftmost_cols = leftmost_prop.local_columns
|
||
|
|
|
||
|
|
leftmost_attr = [
|
||
|
|
getattr(
|
||
|
|
subq_path[0].entity,
|
||
|
|
leftmost_mapper._columntoproperty[c].key)
|
||
|
|
for c in leftmost_cols
|
||
|
|
]
|
||
|
|
|
||
|
|
return leftmost_mapper, leftmost_attr, leftmost_prop
|
||
|
|
|
||
|
|
def _generate_from_original_query(
|
||
|
|
self,
|
||
|
|
orig_query, leftmost_mapper,
|
||
|
|
leftmost_attr, leftmost_relationship, orig_entity
|
||
|
|
):
|
||
|
|
# reformat the original query
|
||
|
|
# to look only for significant columns
|
||
|
|
q = orig_query._clone().correlate(None)
|
||
|
|
|
||
|
|
# set the query's "FROM" list explicitly to what the
|
||
|
|
# FROM list would be in any case, as we will be limiting
|
||
|
|
# the columns in the SELECT list which may no longer include
|
||
|
|
# all entities mentioned in things like WHERE, JOIN, etc.
|
||
|
|
if not q._from_obj:
|
||
|
|
q._set_select_from(
|
||
|
|
list(set([
|
||
|
|
ent['entity'] for ent in orig_query.column_descriptions
|
||
|
|
if ent['entity'] is not None
|
||
|
|
])),
|
||
|
|
False
|
||
|
|
)
|
||
|
|
|
||
|
|
# select from the identity columns of the outer (specifically, these
|
||
|
|
# are the 'local_cols' of the property). This will remove
|
||
|
|
# other columns from the query that might suggest the right entity
|
||
|
|
# which is why we do _set_select_from above.
|
||
|
|
target_cols = q._adapt_col_list(leftmost_attr)
|
||
|
|
q._set_entities(target_cols)
|
||
|
|
|
||
|
|
distinct_target_key = leftmost_relationship.distinct_target_key
|
||
|
|
|
||
|
|
if distinct_target_key is True:
|
||
|
|
q._distinct = True
|
||
|
|
elif distinct_target_key is None:
|
||
|
|
# if target_cols refer to a non-primary key or only
|
||
|
|
# part of a composite primary key, set the q as distinct
|
||
|
|
for t in set(c.table for c in target_cols):
|
||
|
|
if not set(target_cols).issuperset(t.primary_key):
|
||
|
|
q._distinct = True
|
||
|
|
break
|
||
|
|
|
||
|
|
if q._order_by is False:
|
||
|
|
q._order_by = leftmost_mapper.order_by
|
||
|
|
|
||
|
|
# don't need ORDER BY if no limit/offset
|
||
|
|
if q._limit is None and q._offset is None:
|
||
|
|
q._order_by = None
|
||
|
|
|
||
|
|
# the original query now becomes a subquery
|
||
|
|
# which we'll join onto.
|
||
|
|
|
||
|
|
embed_q = q.with_labels().subquery()
|
||
|
|
left_alias = orm_util.AliasedClass(
|
||
|
|
leftmost_mapper, embed_q,
|
||
|
|
use_mapper_path=True)
|
||
|
|
return left_alias
|
||
|
|
|
||
|
|
def _prep_for_joins(self, left_alias, subq_path):
|
||
|
|
# figure out what's being joined. a.k.a. the fun part
|
||
|
|
to_join = []
|
||
|
|
pairs = list(subq_path.pairs())
|
||
|
|
|
||
|
|
for i, (mapper, prop) in enumerate(pairs):
|
||
|
|
if i > 0:
|
||
|
|
# look at the previous mapper in the chain -
|
||
|
|
# if it is as or more specific than this prop's
|
||
|
|
# mapper, use that instead.
|
||
|
|
# note we have an assumption here that
|
||
|
|
# the non-first element is always going to be a mapper,
|
||
|
|
# not an AliasedClass
|
||
|
|
|
||
|
|
prev_mapper = pairs[i - 1][1].mapper
|
||
|
|
to_append = prev_mapper if prev_mapper.isa(mapper) else mapper
|
||
|
|
else:
|
||
|
|
to_append = mapper
|
||
|
|
|
||
|
|
to_join.append((to_append, prop.key))
|
||
|
|
|
||
|
|
# determine the immediate parent class we are joining from,
|
||
|
|
# which needs to be aliased.
|
||
|
|
|
||
|
|
if len(to_join) < 2:
|
||
|
|
# in the case of a one level eager load, this is the
|
||
|
|
# leftmost "left_alias".
|
||
|
|
parent_alias = left_alias
|
||
|
|
else:
|
||
|
|
info = inspect(to_join[-1][0])
|
||
|
|
if info.is_aliased_class:
|
||
|
|
parent_alias = info.entity
|
||
|
|
else:
|
||
|
|
# alias a plain mapper as we may be
|
||
|
|
# joining multiple times
|
||
|
|
parent_alias = orm_util.AliasedClass(
|
||
|
|
info.entity,
|
||
|
|
use_mapper_path=True)
|
||
|
|
|
||
|
|
local_cols = self.parent_property.local_columns
|
||
|
|
|
||
|
|
local_attr = [
|
||
|
|
getattr(parent_alias, self.parent._columntoproperty[c].key)
|
||
|
|
for c in local_cols
|
||
|
|
]
|
||
|
|
return to_join, local_attr, parent_alias
|
||
|
|
|
||
|
|
def _apply_joins(
|
||
|
|
self, q, to_join, left_alias, parent_alias,
|
||
|
|
effective_entity):
|
||
|
|
|
||
|
|
ltj = len(to_join)
|
||
|
|
if ltj == 1:
|
||
|
|
to_join = [
|
||
|
|
getattr(left_alias, to_join[0][1]).of_type(effective_entity)
|
||
|
|
]
|
||
|
|
elif ltj == 2:
|
||
|
|
to_join = [
|
||
|
|
getattr(left_alias, to_join[0][1]).of_type(parent_alias),
|
||
|
|
getattr(parent_alias, to_join[-1][1]).of_type(effective_entity)
|
||
|
|
]
|
||
|
|
elif ltj > 2:
|
||
|
|
middle = [
|
||
|
|
(
|
||
|
|
orm_util.AliasedClass(item[0])
|
||
|
|
if not inspect(item[0]).is_aliased_class
|
||
|
|
else item[0].entity,
|
||
|
|
item[1]
|
||
|
|
) for item in to_join[1:-1]
|
||
|
|
]
|
||
|
|
inner = []
|
||
|
|
|
||
|
|
while middle:
|
||
|
|
item = middle.pop(0)
|
||
|
|
attr = getattr(item[0], item[1])
|
||
|
|
if middle:
|
||
|
|
attr = attr.of_type(middle[0][0])
|
||
|
|
else:
|
||
|
|
attr = attr.of_type(parent_alias)
|
||
|
|
|
||
|
|
inner.append(attr)
|
||
|
|
|
||
|
|
to_join = [
|
||
|
|
getattr(left_alias, to_join[0][1]).of_type(inner[0].parent)
|
||
|
|
] + inner + [
|
||
|
|
getattr(parent_alias, to_join[-1][1]).of_type(effective_entity)
|
||
|
|
]
|
||
|
|
|
||
|
|
for attr in to_join:
|
||
|
|
q = q.join(attr, from_joinpoint=True)
|
||
|
|
return q
|
||
|
|
|
||
|
|
def _setup_options(self, q, subq_path, orig_query, effective_entity):
|
||
|
|
# propagate loader options etc. to the new query.
|
||
|
|
# these will fire relative to subq_path.
|
||
|
|
q = q._with_current_path(subq_path)
|
||
|
|
q = q._conditional_options(*orig_query._with_options)
|
||
|
|
if orig_query._populate_existing:
|
||
|
|
q._populate_existing = orig_query._populate_existing
|
||
|
|
|
||
|
|
return q
|
||
|
|
|
||
|
|
def _setup_outermost_orderby(self, q):
|
||
|
|
if self.parent_property.order_by:
|
||
|
|
# if there's an ORDER BY, alias it the same
|
||
|
|
# way joinedloader does, but we have to pull out
|
||
|
|
# the "eagerjoin" from the query.
|
||
|
|
# this really only picks up the "secondary" table
|
||
|
|
# right now.
|
||
|
|
eagerjoin = q._from_obj[0]
|
||
|
|
eager_order_by = \
|
||
|
|
eagerjoin._target_adapter.\
|
||
|
|
copy_and_process(
|
||
|
|
util.to_list(
|
||
|
|
self.parent_property.order_by
|
||
|
|
)
|
||
|
|
)
|
||
|
|
q = q.order_by(*eager_order_by)
|
||
|
|
return q
|
||
|
|
|
||
|
|
class _SubqCollections(object):
|
||
|
|
"""Given a :class:`.Query` used to emit the "subquery load",
|
||
|
|
provide a load interface that executes the query at the
|
||
|
|
first moment a value is needed.
|
||
|
|
|
||
|
|
"""
|
||
|
|
_data = None
|
||
|
|
|
||
|
|
def __init__(self, subq):
|
||
|
|
self.subq = subq
|
||
|
|
|
||
|
|
def get(self, key, default):
|
||
|
|
if self._data is None:
|
||
|
|
self._load()
|
||
|
|
return self._data.get(key, default)
|
||
|
|
|
||
|
|
def _load(self):
|
||
|
|
self._data = dict(
|
||
|
|
(k, [vv[0] for vv in v])
|
||
|
|
for k, v in itertools.groupby(
|
||
|
|
self.subq,
|
||
|
|
lambda x: x[1:]
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
def loader(self, state, dict_, row):
|
||
|
|
if self._data is None:
|
||
|
|
self._load()
|
||
|
|
|
||
|
|
def create_row_processor(
|
||
|
|
self, context, path, loadopt,
|
||
|
|
mapper, result, adapter, populators):
|
||
|
|
if not self.parent.class_manager[self.key].impl.supports_population:
|
||
|
|
raise sa_exc.InvalidRequestError(
|
||
|
|
"'%s' does not support object "
|
||
|
|
"population - eager loading cannot be applied." %
|
||
|
|
self)
|
||
|
|
|
||
|
|
path = path[self.parent_property]
|
||
|
|
|
||
|
|
subq = path.get(context.attributes, 'subquery')
|
||
|
|
|
||
|
|
if subq is None:
|
||
|
|
return
|
||
|
|
|
||
|
|
assert subq.session is context.session, (
|
||
|
|
"Subquery session doesn't refer to that of "
|
||
|
|
"our context. Are there broken context caching "
|
||
|
|
"schemes being used?"
|
||
|
|
)
|
||
|
|
|
||
|
|
local_cols = self.parent_property.local_columns
|
||
|
|
|
||
|
|
# cache the loaded collections in the context
|
||
|
|
# so that inheriting mappers don't re-load when they
|
||
|
|
# call upon create_row_processor again
|
||
|
|
collections = path.get(context.attributes, "collections")
|
||
|
|
if collections is None:
|
||
|
|
collections = self._SubqCollections(subq)
|
||
|
|
path.set(context.attributes, 'collections', collections)
|
||
|
|
|
||
|
|
if adapter:
|
||
|
|
local_cols = [adapter.columns[c] for c in local_cols]
|
||
|
|
|
||
|
|
if self.uselist:
|
||
|
|
self._create_collection_loader(
|
||
|
|
context, collections, local_cols, populators)
|
||
|
|
else:
|
||
|
|
self._create_scalar_loader(
|
||
|
|
context, collections, local_cols, populators)
|
||
|
|
|
||
|
|
def _create_collection_loader(
|
||
|
|
self, context, collections, local_cols, populators):
|
||
|
|
def load_collection_from_subq(state, dict_, row):
|
||
|
|
collection = collections.get(
|
||
|
|
tuple([row[col] for col in local_cols]),
|
||
|
|
()
|
||
|
|
)
|
||
|
|
state.get_impl(self.key).\
|
||
|
|
set_committed_value(state, dict_, collection)
|
||
|
|
|
||
|
|
def load_collection_from_subq_existing_row(state, dict_, row):
|
||
|
|
if self.key not in dict_:
|
||
|
|
load_collection_from_subq(state, dict_, row)
|
||
|
|
|
||
|
|
populators["new"].append(
|
||
|
|
(self.key, load_collection_from_subq))
|
||
|
|
populators["existing"].append(
|
||
|
|
(self.key, load_collection_from_subq_existing_row))
|
||
|
|
|
||
|
|
if context.invoke_all_eagers:
|
||
|
|
populators["eager"].append((self.key, collections.loader))
|
||
|
|
|
||
|
|
def _create_scalar_loader(
|
||
|
|
self, context, collections, local_cols, populators):
|
||
|
|
def load_scalar_from_subq(state, dict_, row):
|
||
|
|
collection = collections.get(
|
||
|
|
tuple([row[col] for col in local_cols]),
|
||
|
|
(None,)
|
||
|
|
)
|
||
|
|
if len(collection) > 1:
|
||
|
|
util.warn(
|
||
|
|
"Multiple rows returned with "
|
||
|
|
"uselist=False for eagerly-loaded attribute '%s' "
|
||
|
|
% self)
|
||
|
|
|
||
|
|
scalar = collection[0]
|
||
|
|
state.get_impl(self.key).\
|
||
|
|
set_committed_value(state, dict_, scalar)
|
||
|
|
|
||
|
|
def load_scalar_from_subq_existing_row(state, dict_, row):
|
||
|
|
if self.key not in dict_:
|
||
|
|
load_scalar_from_subq(state, dict_, row)
|
||
|
|
|
||
|
|
populators["new"].append(
|
||
|
|
(self.key, load_scalar_from_subq))
|
||
|
|
populators["existing"].append(
|
||
|
|
(self.key, load_scalar_from_subq_existing_row))
|
||
|
|
if context.invoke_all_eagers:
|
||
|
|
populators["eager"].append((self.key, collections.loader))
|
||
|
|
|
||
|
|
|
||
|
|
@log.class_logger
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy="joined")
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy=False)
|
||
|
|
class JoinedLoader(AbstractRelationshipLoader):
|
||
|
|
"""Provide loading behavior for a :class:`.RelationshipProperty`
|
||
|
|
using joined eager loading.
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
__slots__ = 'join_depth', '_aliased_class_pool'
|
||
|
|
|
||
|
|
def __init__(self, parent, strategy_key):
|
||
|
|
super(JoinedLoader, self).__init__(parent, strategy_key)
|
||
|
|
self.join_depth = self.parent_property.join_depth
|
||
|
|
self._aliased_class_pool = []
|
||
|
|
|
||
|
|
def init_class_attribute(self, mapper):
|
||
|
|
self.parent_property.\
|
||
|
|
_get_strategy((("lazy", "select"),)).init_class_attribute(mapper)
|
||
|
|
|
||
|
|
def setup_query(
|
||
|
|
self, context, entity, path, loadopt, adapter,
|
||
|
|
column_collection=None, parentmapper=None,
|
||
|
|
chained_from_outerjoin=False,
|
||
|
|
**kwargs):
|
||
|
|
"""Add a left outer join to the statement that's being constructed."""
|
||
|
|
|
||
|
|
if not context.query._enable_eagerloads:
|
||
|
|
return
|
||
|
|
elif context.query._yield_per and self.uselist:
|
||
|
|
context.query._no_yield_per("joined collection")
|
||
|
|
|
||
|
|
path = path[self.parent_property]
|
||
|
|
|
||
|
|
with_polymorphic = None
|
||
|
|
|
||
|
|
user_defined_adapter = self._init_user_defined_eager_proc(
|
||
|
|
loadopt, context) if loadopt else False
|
||
|
|
|
||
|
|
if user_defined_adapter is not False:
|
||
|
|
clauses, adapter, add_to_collection = \
|
||
|
|
self._setup_query_on_user_defined_adapter(
|
||
|
|
context, entity, path, adapter,
|
||
|
|
user_defined_adapter
|
||
|
|
)
|
||
|
|
else:
|
||
|
|
# if not via query option, check for
|
||
|
|
# a cycle
|
||
|
|
if not path.contains(context.attributes, "loader"):
|
||
|
|
if self.join_depth:
|
||
|
|
if path.length / 2 > self.join_depth:
|
||
|
|
return
|
||
|
|
elif path.contains_mapper(self.mapper):
|
||
|
|
return
|
||
|
|
|
||
|
|
clauses, adapter, add_to_collection, chained_from_outerjoin = \
|
||
|
|
self._generate_row_adapter(
|
||
|
|
context, entity, path, loadopt, adapter,
|
||
|
|
column_collection, parentmapper, chained_from_outerjoin
|
||
|
|
)
|
||
|
|
|
||
|
|
with_poly_info = path.get(
|
||
|
|
context.attributes,
|
||
|
|
"path_with_polymorphic",
|
||
|
|
None
|
||
|
|
)
|
||
|
|
if with_poly_info is not None:
|
||
|
|
with_polymorphic = with_poly_info.with_polymorphic_mappers
|
||
|
|
else:
|
||
|
|
with_polymorphic = None
|
||
|
|
|
||
|
|
path = path[self.mapper]
|
||
|
|
|
||
|
|
loading._setup_entity_query(
|
||
|
|
context, self.mapper, entity,
|
||
|
|
path, clauses, add_to_collection,
|
||
|
|
with_polymorphic=with_polymorphic,
|
||
|
|
parentmapper=self.mapper,
|
||
|
|
chained_from_outerjoin=chained_from_outerjoin)
|
||
|
|
|
||
|
|
if with_poly_info is not None and \
|
||
|
|
None in set(context.secondary_columns):
|
||
|
|
raise sa_exc.InvalidRequestError(
|
||
|
|
"Detected unaliased columns when generating joined "
|
||
|
|
"load. Make sure to use aliased=True or flat=True "
|
||
|
|
"when using joined loading with with_polymorphic()."
|
||
|
|
)
|
||
|
|
|
||
|
|
def _init_user_defined_eager_proc(self, loadopt, context):
|
||
|
|
|
||
|
|
# check if the opt applies at all
|
||
|
|
if "eager_from_alias" not in loadopt.local_opts:
|
||
|
|
# nope
|
||
|
|
return False
|
||
|
|
|
||
|
|
path = loadopt.path.parent
|
||
|
|
|
||
|
|
# the option applies. check if the "user_defined_eager_row_processor"
|
||
|
|
# has been built up.
|
||
|
|
adapter = path.get(
|
||
|
|
context.attributes,
|
||
|
|
"user_defined_eager_row_processor", False)
|
||
|
|
if adapter is not False:
|
||
|
|
# just return it
|
||
|
|
return adapter
|
||
|
|
|
||
|
|
# otherwise figure it out.
|
||
|
|
alias = loadopt.local_opts["eager_from_alias"]
|
||
|
|
|
||
|
|
root_mapper, prop = path[-2:]
|
||
|
|
|
||
|
|
#from .mapper import Mapper
|
||
|
|
#from .interfaces import MapperProperty
|
||
|
|
#assert isinstance(root_mapper, Mapper)
|
||
|
|
#assert isinstance(prop, MapperProperty)
|
||
|
|
|
||
|
|
if alias is not None:
|
||
|
|
if isinstance(alias, str):
|
||
|
|
alias = prop.target.alias(alias)
|
||
|
|
adapter = sql_util.ColumnAdapter(
|
||
|
|
alias,
|
||
|
|
equivalents=prop.mapper._equivalent_columns)
|
||
|
|
else:
|
||
|
|
if path.contains(context.attributes, "path_with_polymorphic"):
|
||
|
|
with_poly_info = path.get(
|
||
|
|
context.attributes,
|
||
|
|
"path_with_polymorphic")
|
||
|
|
adapter = orm_util.ORMAdapter(
|
||
|
|
with_poly_info.entity,
|
||
|
|
equivalents=prop.mapper._equivalent_columns)
|
||
|
|
else:
|
||
|
|
adapter = context.query._polymorphic_adapters.get(
|
||
|
|
prop.mapper, None)
|
||
|
|
path.set(
|
||
|
|
context.attributes,
|
||
|
|
"user_defined_eager_row_processor",
|
||
|
|
adapter)
|
||
|
|
|
||
|
|
return adapter
|
||
|
|
|
||
|
|
def _setup_query_on_user_defined_adapter(
|
||
|
|
self, context, entity,
|
||
|
|
path, adapter, user_defined_adapter):
|
||
|
|
|
||
|
|
# apply some more wrapping to the "user defined adapter"
|
||
|
|
# if we are setting up the query for SQL render.
|
||
|
|
adapter = entity._get_entity_clauses(context.query, context)
|
||
|
|
|
||
|
|
if adapter and user_defined_adapter:
|
||
|
|
user_defined_adapter = user_defined_adapter.wrap(adapter)
|
||
|
|
path.set(
|
||
|
|
context.attributes, "user_defined_eager_row_processor",
|
||
|
|
user_defined_adapter)
|
||
|
|
elif adapter:
|
||
|
|
user_defined_adapter = adapter
|
||
|
|
path.set(
|
||
|
|
context.attributes, "user_defined_eager_row_processor",
|
||
|
|
user_defined_adapter)
|
||
|
|
|
||
|
|
add_to_collection = context.primary_columns
|
||
|
|
return user_defined_adapter, adapter, add_to_collection
|
||
|
|
|
||
|
|
def _gen_pooled_aliased_class(self, context):
|
||
|
|
# keep a local pool of AliasedClass objects that get re-used.
|
||
|
|
# we need one unique AliasedClass per query per appearance of our
|
||
|
|
# entity in the query.
|
||
|
|
|
||
|
|
key = ('joinedloader_ac', self)
|
||
|
|
if key not in context.attributes:
|
||
|
|
context.attributes[key] = idx = 0
|
||
|
|
else:
|
||
|
|
context.attributes[key] = idx = context.attributes[key] + 1
|
||
|
|
|
||
|
|
if idx >= len(self._aliased_class_pool):
|
||
|
|
to_adapt = orm_util.AliasedClass(
|
||
|
|
self.mapper,
|
||
|
|
flat=True,
|
||
|
|
use_mapper_path=True)
|
||
|
|
# load up the .columns collection on the Alias() before
|
||
|
|
# the object becomes shared among threads. this prevents
|
||
|
|
# races for column identities.
|
||
|
|
inspect(to_adapt).selectable.c
|
||
|
|
|
||
|
|
self._aliased_class_pool.append(to_adapt)
|
||
|
|
|
||
|
|
return self._aliased_class_pool[idx]
|
||
|
|
|
||
|
|
def _generate_row_adapter(
|
||
|
|
self,
|
||
|
|
context, entity, path, loadopt, adapter,
|
||
|
|
column_collection, parentmapper, chained_from_outerjoin):
|
||
|
|
with_poly_info = path.get(
|
||
|
|
context.attributes,
|
||
|
|
"path_with_polymorphic",
|
||
|
|
None
|
||
|
|
)
|
||
|
|
if with_poly_info:
|
||
|
|
to_adapt = with_poly_info.entity
|
||
|
|
else:
|
||
|
|
to_adapt = self._gen_pooled_aliased_class(context)
|
||
|
|
|
||
|
|
clauses = inspect(to_adapt)._memo(
|
||
|
|
("joinedloader_ormadapter", self),
|
||
|
|
orm_util.ORMAdapter,
|
||
|
|
to_adapt,
|
||
|
|
equivalents=self.mapper._equivalent_columns,
|
||
|
|
adapt_required=True, allow_label_resolve=False,
|
||
|
|
anonymize_labels=True
|
||
|
|
)
|
||
|
|
|
||
|
|
assert clauses.aliased_class is not None
|
||
|
|
|
||
|
|
if self.parent_property.uselist:
|
||
|
|
context.multi_row_eager_loaders = True
|
||
|
|
|
||
|
|
innerjoin = (
|
||
|
|
loadopt.local_opts.get(
|
||
|
|
'innerjoin', self.parent_property.innerjoin)
|
||
|
|
if loadopt is not None
|
||
|
|
else self.parent_property.innerjoin
|
||
|
|
)
|
||
|
|
|
||
|
|
if not innerjoin:
|
||
|
|
# if this is an outer join, all non-nested eager joins from
|
||
|
|
# this path must also be outer joins
|
||
|
|
chained_from_outerjoin = True
|
||
|
|
|
||
|
|
context.create_eager_joins.append(
|
||
|
|
(
|
||
|
|
self._create_eager_join, context,
|
||
|
|
entity, path, adapter,
|
||
|
|
parentmapper, clauses, innerjoin, chained_from_outerjoin
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
add_to_collection = context.secondary_columns
|
||
|
|
path.set(context.attributes, "eager_row_processor", clauses)
|
||
|
|
|
||
|
|
return clauses, adapter, add_to_collection, chained_from_outerjoin
|
||
|
|
|
||
|
|
def _create_eager_join(
|
||
|
|
self, context, entity,
|
||
|
|
path, adapter, parentmapper,
|
||
|
|
clauses, innerjoin, chained_from_outerjoin):
|
||
|
|
|
||
|
|
if parentmapper is None:
|
||
|
|
localparent = entity.mapper
|
||
|
|
else:
|
||
|
|
localparent = parentmapper
|
||
|
|
|
||
|
|
# whether or not the Query will wrap the selectable in a subquery,
|
||
|
|
# and then attach eager load joins to that (i.e., in the case of
|
||
|
|
# LIMIT/OFFSET etc.)
|
||
|
|
should_nest_selectable = context.multi_row_eager_loaders and \
|
||
|
|
context.query._should_nest_selectable
|
||
|
|
|
||
|
|
entity_key = None
|
||
|
|
|
||
|
|
if entity not in context.eager_joins and \
|
||
|
|
not should_nest_selectable and \
|
||
|
|
context.from_clause:
|
||
|
|
index, clause = sql_util.find_join_source(
|
||
|
|
context.from_clause, entity.selectable)
|
||
|
|
if clause is not None:
|
||
|
|
# join to an existing FROM clause on the query.
|
||
|
|
# key it to its list index in the eager_joins dict.
|
||
|
|
# Query._compile_context will adapt as needed and
|
||
|
|
# append to the FROM clause of the select().
|
||
|
|
entity_key, default_towrap = index, clause
|
||
|
|
|
||
|
|
if entity_key is None:
|
||
|
|
entity_key, default_towrap = entity, entity.selectable
|
||
|
|
|
||
|
|
towrap = context.eager_joins.setdefault(entity_key, default_towrap)
|
||
|
|
|
||
|
|
if adapter:
|
||
|
|
if getattr(adapter, 'aliased_class', None):
|
||
|
|
# joining from an adapted entity. The adapted entity
|
||
|
|
# might be a "with_polymorphic", so resolve that to our
|
||
|
|
# specific mapper's entity before looking for our attribute
|
||
|
|
# name on it.
|
||
|
|
efm = inspect(adapter.aliased_class).\
|
||
|
|
_entity_for_mapper(
|
||
|
|
localparent
|
||
|
|
if localparent.isa(self.parent) else self.parent)
|
||
|
|
|
||
|
|
# look for our attribute on the adapted entity, else fall back
|
||
|
|
# to our straight property
|
||
|
|
onclause = getattr(
|
||
|
|
efm.entity, self.key,
|
||
|
|
self.parent_property)
|
||
|
|
else:
|
||
|
|
onclause = getattr(
|
||
|
|
orm_util.AliasedClass(
|
||
|
|
self.parent,
|
||
|
|
adapter.selectable,
|
||
|
|
use_mapper_path=True
|
||
|
|
),
|
||
|
|
self.key, self.parent_property
|
||
|
|
)
|
||
|
|
|
||
|
|
else:
|
||
|
|
onclause = self.parent_property
|
||
|
|
|
||
|
|
assert clauses.aliased_class is not None
|
||
|
|
|
||
|
|
attach_on_outside = (
|
||
|
|
not chained_from_outerjoin or
|
||
|
|
not innerjoin or innerjoin == 'unnested' or
|
||
|
|
entity.entity_zero.represents_outer_join
|
||
|
|
)
|
||
|
|
|
||
|
|
if attach_on_outside:
|
||
|
|
# this is the "classic" eager join case.
|
||
|
|
eagerjoin = orm_util._ORMJoin(
|
||
|
|
towrap,
|
||
|
|
clauses.aliased_class,
|
||
|
|
onclause,
|
||
|
|
isouter=not innerjoin or
|
||
|
|
entity.entity_zero.represents_outer_join or
|
||
|
|
(
|
||
|
|
chained_from_outerjoin and isinstance(towrap, sql.Join)
|
||
|
|
), _left_memo=self.parent, _right_memo=self.mapper
|
||
|
|
)
|
||
|
|
else:
|
||
|
|
# all other cases are innerjoin=='nested' approach
|
||
|
|
eagerjoin = self._splice_nested_inner_join(
|
||
|
|
path, towrap, clauses, onclause)
|
||
|
|
|
||
|
|
context.eager_joins[entity_key] = eagerjoin
|
||
|
|
|
||
|
|
# send a hint to the Query as to where it may "splice" this join
|
||
|
|
eagerjoin.stop_on = entity.selectable
|
||
|
|
|
||
|
|
if not parentmapper:
|
||
|
|
# for parentclause that is the non-eager end of the join,
|
||
|
|
# ensure all the parent cols in the primaryjoin are actually
|
||
|
|
# in the
|
||
|
|
# columns clause (i.e. are not deferred), so that aliasing applied
|
||
|
|
# by the Query propagates those columns outward.
|
||
|
|
# This has the effect
|
||
|
|
# of "undefering" those columns.
|
||
|
|
for col in sql_util._find_columns(
|
||
|
|
self.parent_property.primaryjoin):
|
||
|
|
if localparent.mapped_table.c.contains_column(col):
|
||
|
|
if adapter:
|
||
|
|
col = adapter.columns[col]
|
||
|
|
context.primary_columns.append(col)
|
||
|
|
|
||
|
|
if self.parent_property.order_by:
|
||
|
|
context.eager_order_by += eagerjoin._target_adapter.\
|
||
|
|
copy_and_process(
|
||
|
|
util.to_list(
|
||
|
|
self.parent_property.order_by
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
def _splice_nested_inner_join(
|
||
|
|
self, path, join_obj, clauses, onclause, splicing=False):
|
||
|
|
|
||
|
|
if splicing is False:
|
||
|
|
# first call is always handed a join object
|
||
|
|
# from the outside
|
||
|
|
assert isinstance(join_obj, orm_util._ORMJoin)
|
||
|
|
elif isinstance(join_obj, sql.selectable.FromGrouping):
|
||
|
|
return self._splice_nested_inner_join(
|
||
|
|
path, join_obj.element, clauses, onclause, splicing
|
||
|
|
)
|
||
|
|
elif not isinstance(join_obj, orm_util._ORMJoin):
|
||
|
|
if path[-2] is splicing:
|
||
|
|
return orm_util._ORMJoin(
|
||
|
|
join_obj, clauses.aliased_class,
|
||
|
|
onclause, isouter=False,
|
||
|
|
_left_memo=splicing,
|
||
|
|
_right_memo=path[-1].mapper
|
||
|
|
)
|
||
|
|
else:
|
||
|
|
# only here if splicing == True
|
||
|
|
return None
|
||
|
|
|
||
|
|
target_join = self._splice_nested_inner_join(
|
||
|
|
path, join_obj.right, clauses,
|
||
|
|
onclause, join_obj._right_memo)
|
||
|
|
if target_join is None:
|
||
|
|
right_splice = False
|
||
|
|
target_join = self._splice_nested_inner_join(
|
||
|
|
path, join_obj.left, clauses,
|
||
|
|
onclause, join_obj._left_memo)
|
||
|
|
if target_join is None:
|
||
|
|
# should only return None when recursively called,
|
||
|
|
# e.g. splicing==True
|
||
|
|
assert splicing is not False, \
|
||
|
|
"assertion failed attempting to produce joined eager loads"
|
||
|
|
return None
|
||
|
|
else:
|
||
|
|
right_splice = True
|
||
|
|
|
||
|
|
if right_splice:
|
||
|
|
# for a right splice, attempt to flatten out
|
||
|
|
# a JOIN b JOIN c JOIN .. to avoid needless
|
||
|
|
# parenthesis nesting
|
||
|
|
if not join_obj.isouter and not target_join.isouter:
|
||
|
|
eagerjoin = join_obj._splice_into_center(target_join)
|
||
|
|
else:
|
||
|
|
eagerjoin = orm_util._ORMJoin(
|
||
|
|
join_obj.left, target_join,
|
||
|
|
join_obj.onclause, isouter=join_obj.isouter,
|
||
|
|
_left_memo=join_obj._left_memo)
|
||
|
|
else:
|
||
|
|
eagerjoin = orm_util._ORMJoin(
|
||
|
|
target_join, join_obj.right,
|
||
|
|
join_obj.onclause, isouter=join_obj.isouter,
|
||
|
|
_right_memo=join_obj._right_memo)
|
||
|
|
|
||
|
|
eagerjoin._target_adapter = target_join._target_adapter
|
||
|
|
return eagerjoin
|
||
|
|
|
||
|
|
def _create_eager_adapter(self, context, result, adapter, path, loadopt):
|
||
|
|
user_defined_adapter = self._init_user_defined_eager_proc(
|
||
|
|
loadopt, context) if loadopt else False
|
||
|
|
|
||
|
|
if user_defined_adapter is not False:
|
||
|
|
decorator = user_defined_adapter
|
||
|
|
# user defined eagerloads are part of the "primary"
|
||
|
|
# portion of the load.
|
||
|
|
# the adapters applied to the Query should be honored.
|
||
|
|
if context.adapter and decorator:
|
||
|
|
decorator = decorator.wrap(context.adapter)
|
||
|
|
elif context.adapter:
|
||
|
|
decorator = context.adapter
|
||
|
|
else:
|
||
|
|
decorator = path.get(context.attributes, "eager_row_processor")
|
||
|
|
if decorator is None:
|
||
|
|
return False
|
||
|
|
|
||
|
|
if self.mapper._result_has_identity_key(result, decorator):
|
||
|
|
return decorator
|
||
|
|
else:
|
||
|
|
# no identity key - don't return a row
|
||
|
|
# processor, will cause a degrade to lazy
|
||
|
|
return False
|
||
|
|
|
||
|
|
def create_row_processor(
|
||
|
|
self, context, path, loadopt, mapper,
|
||
|
|
result, adapter, populators):
|
||
|
|
if not self.parent.class_manager[self.key].impl.supports_population:
|
||
|
|
raise sa_exc.InvalidRequestError(
|
||
|
|
"'%s' does not support object "
|
||
|
|
"population - eager loading cannot be applied." %
|
||
|
|
self
|
||
|
|
)
|
||
|
|
|
||
|
|
our_path = path[self.parent_property]
|
||
|
|
|
||
|
|
eager_adapter = self._create_eager_adapter(
|
||
|
|
context,
|
||
|
|
result,
|
||
|
|
adapter, our_path, loadopt)
|
||
|
|
|
||
|
|
if eager_adapter is not False:
|
||
|
|
key = self.key
|
||
|
|
|
||
|
|
_instance = loading._instance_processor(
|
||
|
|
self.mapper,
|
||
|
|
context,
|
||
|
|
result,
|
||
|
|
our_path[self.mapper],
|
||
|
|
eager_adapter)
|
||
|
|
|
||
|
|
if not self.uselist:
|
||
|
|
self._create_scalar_loader(context, key, _instance, populators)
|
||
|
|
else:
|
||
|
|
self._create_collection_loader(
|
||
|
|
context, key, _instance, populators)
|
||
|
|
else:
|
||
|
|
self.parent_property._get_strategy((("lazy", "select"),)).\
|
||
|
|
create_row_processor(
|
||
|
|
context, path, loadopt,
|
||
|
|
mapper, result, adapter, populators)
|
||
|
|
|
||
|
|
def _create_collection_loader(self, context, key, _instance, populators):
|
||
|
|
def load_collection_from_joined_new_row(state, dict_, row):
|
||
|
|
collection = attributes.init_state_collection(
|
||
|
|
state, dict_, key)
|
||
|
|
result_list = util.UniqueAppender(collection,
|
||
|
|
'append_without_event')
|
||
|
|
context.attributes[(state, key)] = result_list
|
||
|
|
inst = _instance(row)
|
||
|
|
if inst is not None:
|
||
|
|
result_list.append(inst)
|
||
|
|
|
||
|
|
def load_collection_from_joined_existing_row(state, dict_, row):
|
||
|
|
if (state, key) in context.attributes:
|
||
|
|
result_list = context.attributes[(state, key)]
|
||
|
|
else:
|
||
|
|
# appender_key can be absent from context.attributes
|
||
|
|
# with isnew=False when self-referential eager loading
|
||
|
|
# is used; the same instance may be present in two
|
||
|
|
# distinct sets of result columns
|
||
|
|
collection = attributes.init_state_collection(
|
||
|
|
state, dict_, key)
|
||
|
|
result_list = util.UniqueAppender(
|
||
|
|
collection,
|
||
|
|
'append_without_event')
|
||
|
|
context.attributes[(state, key)] = result_list
|
||
|
|
inst = _instance(row)
|
||
|
|
if inst is not None:
|
||
|
|
result_list.append(inst)
|
||
|
|
|
||
|
|
def load_collection_from_joined_exec(state, dict_, row):
|
||
|
|
_instance(row)
|
||
|
|
|
||
|
|
populators["new"].append((self.key, load_collection_from_joined_new_row))
|
||
|
|
populators["existing"].append(
|
||
|
|
(self.key, load_collection_from_joined_existing_row))
|
||
|
|
if context.invoke_all_eagers:
|
||
|
|
populators["eager"].append(
|
||
|
|
(self.key, load_collection_from_joined_exec))
|
||
|
|
|
||
|
|
def _create_scalar_loader(self, context, key, _instance, populators):
|
||
|
|
def load_scalar_from_joined_new_row(state, dict_, row):
|
||
|
|
# set a scalar object instance directly on the parent
|
||
|
|
# object, bypassing InstrumentedAttribute event handlers.
|
||
|
|
dict_[key] = _instance(row)
|
||
|
|
|
||
|
|
def load_scalar_from_joined_existing_row(state, dict_, row):
|
||
|
|
# call _instance on the row, even though the object has
|
||
|
|
# been created, so that we further descend into properties
|
||
|
|
existing = _instance(row)
|
||
|
|
|
||
|
|
# conflicting value already loaded, this shouldn't happen
|
||
|
|
if key in dict_:
|
||
|
|
if existing is not dict_[key]:
|
||
|
|
util.warn(
|
||
|
|
"Multiple rows returned with "
|
||
|
|
"uselist=False for eagerly-loaded attribute '%s' "
|
||
|
|
% self)
|
||
|
|
else:
|
||
|
|
# this case is when one row has multiple loads of the
|
||
|
|
# same entity (e.g. via aliasing), one has an attribute
|
||
|
|
# that the other doesn't.
|
||
|
|
dict_[key] = existing
|
||
|
|
|
||
|
|
def load_scalar_from_joined_exec(state, dict_, row):
|
||
|
|
_instance(row)
|
||
|
|
|
||
|
|
populators["new"].append((self.key, load_scalar_from_joined_new_row))
|
||
|
|
populators["existing"].append(
|
||
|
|
(self.key, load_scalar_from_joined_existing_row))
|
||
|
|
if context.invoke_all_eagers:
|
||
|
|
populators["eager"].append((self.key, load_scalar_from_joined_exec))
|
||
|
|
|
||
|
|
|
||
|
|
@log.class_logger
|
||
|
|
@properties.RelationshipProperty.strategy_for(lazy="selectin")
|
||
|
|
class SelectInLoader(AbstractRelationshipLoader, util.MemoizedSlots):
|
||
|
|
__slots__ = (
|
||
|
|
'join_depth', '_parent_alias', '_in_expr', '_parent_pk_cols',
|
||
|
|
'_zero_idx', '_bakery'
|
||
|
|
)
|
||
|
|
|
||
|
|
_chunksize = 500
|
||
|
|
|
||
|
|
def __init__(self, parent, strategy_key):
|
||
|
|
super(SelectInLoader, self).__init__(parent, strategy_key)
|
||
|
|
self.join_depth = self.parent_property.join_depth
|
||
|
|
self._parent_alias = aliased(self.parent.class_)
|
||
|
|
pa_insp = inspect(self._parent_alias)
|
||
|
|
self._parent_pk_cols = pk_cols = [
|
||
|
|
pa_insp._adapt_element(col) for col in self.parent.primary_key]
|
||
|
|
if len(pk_cols) > 1:
|
||
|
|
self._in_expr = sql.tuple_(*pk_cols)
|
||
|
|
self._zero_idx = False
|
||
|
|
else:
|
||
|
|
self._in_expr = pk_cols[0]
|
||
|
|
self._zero_idx = True
|
||
|
|
|
||
|
|
def init_class_attribute(self, mapper):
|
||
|
|
self.parent_property.\
|
||
|
|
_get_strategy((("lazy", "select"),)).\
|
||
|
|
init_class_attribute(mapper)
|
||
|
|
|
||
|
|
@util.dependencies("sqlalchemy.ext.baked")
|
||
|
|
def _memoized_attr__bakery(self, baked):
|
||
|
|
return baked.bakery(size=50)
|
||
|
|
|
||
|
|
def create_row_processor(
|
||
|
|
self, context, path, loadopt, mapper,
|
||
|
|
result, adapter, populators):
|
||
|
|
if not self.parent.class_manager[self.key].impl.supports_population:
|
||
|
|
raise sa_exc.InvalidRequestError(
|
||
|
|
"'%s' does not support object "
|
||
|
|
"population - eager loading cannot be applied." %
|
||
|
|
self
|
||
|
|
)
|
||
|
|
|
||
|
|
selectin_path = (
|
||
|
|
context.query._current_path or orm_util.PathRegistry.root) + path
|
||
|
|
|
||
|
|
if not orm_util._entity_isa(path[-1], self.parent):
|
||
|
|
return
|
||
|
|
|
||
|
|
if loading.PostLoad.path_exists(context, selectin_path, self.key):
|
||
|
|
return
|
||
|
|
|
||
|
|
path_w_prop = path[self.parent_property]
|
||
|
|
selectin_path_w_prop = selectin_path[self.parent_property]
|
||
|
|
|
||
|
|
# build up a path indicating the path from the leftmost
|
||
|
|
# entity to the thing we're subquery loading.
|
||
|
|
with_poly_info = path_w_prop.get(
|
||
|
|
context.attributes,
|
||
|
|
"path_with_polymorphic", None)
|
||
|
|
|
||
|
|
if with_poly_info is not None:
|
||
|
|
effective_entity = with_poly_info.entity
|
||
|
|
else:
|
||
|
|
effective_entity = self.mapper
|
||
|
|
|
||
|
|
if not path_w_prop.contains(context.attributes, "loader"):
|
||
|
|
if self.join_depth:
|
||
|
|
if selectin_path_w_prop.length / 2 > self.join_depth:
|
||
|
|
return
|
||
|
|
elif selectin_path_w_prop.contains_mapper(self.mapper):
|
||
|
|
return
|
||
|
|
|
||
|
|
loading.PostLoad.callable_for_path(
|
||
|
|
context, selectin_path, self.parent, self.key,
|
||
|
|
self._load_for_path, effective_entity)
|
||
|
|
|
||
|
|
@util.dependencies("sqlalchemy.ext.baked")
|
||
|
|
def _load_for_path(
|
||
|
|
self, baked, context, path, states, load_only, effective_entity):
|
||
|
|
|
||
|
|
if load_only and self.key not in load_only:
|
||
|
|
return
|
||
|
|
|
||
|
|
our_states = [
|
||
|
|
(state.key[1], state, overwrite)
|
||
|
|
for state, overwrite in states
|
||
|
|
]
|
||
|
|
|
||
|
|
pk_cols = self._parent_pk_cols
|
||
|
|
pa = self._parent_alias
|
||
|
|
|
||
|
|
q = self._bakery(
|
||
|
|
lambda session: session.query(
|
||
|
|
query.Bundle("pk", *pk_cols), effective_entity,
|
||
|
|
), self
|
||
|
|
)
|
||
|
|
|
||
|
|
q.add_criteria(
|
||
|
|
lambda q: q.select_from(pa).join(
|
||
|
|
getattr(pa,
|
||
|
|
self.parent_property.key).of_type(effective_entity)).
|
||
|
|
filter(
|
||
|
|
self._in_expr.in_(
|
||
|
|
sql.bindparam('primary_keys', expanding=True))
|
||
|
|
).order_by(*pk_cols)
|
||
|
|
)
|
||
|
|
|
||
|
|
orig_query = context.query
|
||
|
|
|
||
|
|
q._add_lazyload_options(
|
||
|
|
orig_query._with_options,
|
||
|
|
path[self.parent_property]
|
||
|
|
)
|
||
|
|
|
||
|
|
if orig_query._populate_existing:
|
||
|
|
q.add_criteria(
|
||
|
|
lambda q: q.populate_existing()
|
||
|
|
)
|
||
|
|
|
||
|
|
if self.parent_property.order_by:
|
||
|
|
def _setup_outermost_orderby(q):
|
||
|
|
# imitate the same method that
|
||
|
|
# subquery eager loading does it, looking for the
|
||
|
|
# adapted "secondary" table
|
||
|
|
eagerjoin = q._from_obj[0]
|
||
|
|
eager_order_by = \
|
||
|
|
eagerjoin._target_adapter.\
|
||
|
|
copy_and_process(
|
||
|
|
util.to_list(
|
||
|
|
self.parent_property.order_by
|
||
|
|
)
|
||
|
|
)
|
||
|
|
return q.order_by(*eager_order_by)
|
||
|
|
|
||
|
|
q.add_criteria(
|
||
|
|
_setup_outermost_orderby
|
||
|
|
)
|
||
|
|
|
||
|
|
uselist = self.uselist
|
||
|
|
_empty_result = () if uselist else None
|
||
|
|
|
||
|
|
while our_states:
|
||
|
|
chunk = our_states[0:self._chunksize]
|
||
|
|
our_states = our_states[self._chunksize:]
|
||
|
|
|
||
|
|
data = {
|
||
|
|
k: [vv[1] for vv in v]
|
||
|
|
for k, v in itertools.groupby(
|
||
|
|
q(context.session).params(
|
||
|
|
primary_keys=[
|
||
|
|
key[0] if self._zero_idx else key
|
||
|
|
for key, state, overwrite in chunk]
|
||
|
|
),
|
||
|
|
lambda x: x[0]
|
||
|
|
)
|
||
|
|
}
|
||
|
|
|
||
|
|
for key, state, overwrite in chunk:
|
||
|
|
|
||
|
|
if not overwrite and self.key in state.dict:
|
||
|
|
continue
|
||
|
|
|
||
|
|
collection = data.get(key, _empty_result)
|
||
|
|
|
||
|
|
if not uselist and collection:
|
||
|
|
if len(collection) > 1:
|
||
|
|
util.warn(
|
||
|
|
"Multiple rows returned with "
|
||
|
|
"uselist=False for eagerly-loaded "
|
||
|
|
"attribute '%s' "
|
||
|
|
% self)
|
||
|
|
state.get_impl(self.key).set_committed_value(
|
||
|
|
state, state.dict, collection[0])
|
||
|
|
else:
|
||
|
|
state.get_impl(self.key).set_committed_value(
|
||
|
|
state, state.dict, collection)
|
||
|
|
|
||
|
|
|
||
|
|
def single_parent_validator(desc, prop):
|
||
|
|
def _do_check(state, value, oldvalue, initiator):
|
||
|
|
if value is not None and initiator.key == prop.key:
|
||
|
|
hasparent = initiator.hasparent(attributes.instance_state(value))
|
||
|
|
if hasparent and oldvalue is not value:
|
||
|
|
raise sa_exc.InvalidRequestError(
|
||
|
|
"Instance %s is already associated with an instance "
|
||
|
|
"of %s via its %s attribute, and is only allowed a "
|
||
|
|
"single parent." %
|
||
|
|
(orm_util.instance_str(value), state.class_, prop)
|
||
|
|
)
|
||
|
|
return value
|
||
|
|
|
||
|
|
def append(state, value, initiator):
|
||
|
|
return _do_check(state, value, None, initiator)
|
||
|
|
|
||
|
|
def set_(state, value, oldvalue, initiator):
|
||
|
|
return _do_check(state, value, oldvalue, initiator)
|
||
|
|
|
||
|
|
event.listen(
|
||
|
|
desc, 'append', append, raw=True, retval=True,
|
||
|
|
active_history=True)
|
||
|
|
event.listen(
|
||
|
|
desc, 'set', set_, raw=True, retval=True,
|
||
|
|
active_history=True)
|