Mini Shell
# orm/persistence.py
# Copyright (C) 2005-2021 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
"""private module containing functions used to emit INSERT, UPDATE
and DELETE statements on behalf of a :class:`_orm.Mapper` and its descending
mappers.
The functions here are called only by the unit of work functions
in unitofwork.py.
"""
from itertools import chain
from itertools import groupby
import operator
from . import attributes
from . import evaluator
from . import exc as orm_exc
from . import loading
from . import sync
from .base import _entity_descriptor
from .base import state_str
from .. import exc as sa_exc
from .. import sql
from .. import util
from ..sql import expression
from ..sql.base import _from_objects
def _bulk_insert(
mapper,
mappings,
session_transaction,
isstates,
return_defaults,
render_nulls,
):
base_mapper = mapper.base_mapper
cached_connections = _cached_connection_dict(base_mapper)
if session_transaction.session.connection_callable:
raise NotImplementedError(
"connection_callable / per-instance sharding "
"not supported in bulk_insert()"
)
if isstates:
if return_defaults:
states = [(state, state.dict) for state in mappings]
mappings = [dict_ for (state, dict_) in states]
else:
mappings = [state.dict for state in mappings]
else:
mappings = list(mappings)
connection = session_transaction.connection(base_mapper)
for table, super_mapper in base_mapper._sorted_tables.items():
if not mapper.isa(super_mapper):
continue
records = (
(
None,
state_dict,
params,
mapper,
connection,
value_params,
has_all_pks,
has_all_defaults,
)
for (
state,
state_dict,
params,
mp,
conn,
value_params,
has_all_pks,
has_all_defaults,
) in _collect_insert_commands(
table,
((None, mapping, mapper, connection) for mapping in mappings),
bulk=True,
return_defaults=return_defaults,
render_nulls=render_nulls,
)
)
_emit_insert_statements(
base_mapper,
None,
cached_connections,
super_mapper,
table,
records,
bookkeeping=return_defaults,
)
if return_defaults and isstates:
identity_cls = mapper._identity_class
identity_props = [p.key for p in mapper._identity_key_props]
for state, dict_ in states:
state.key = (
identity_cls,
tuple([dict_[key] for key in identity_props]),
)
def _bulk_update(
mapper, mappings, session_transaction, isstates, update_changed_only
):
base_mapper = mapper.base_mapper
cached_connections = _cached_connection_dict(base_mapper)
search_keys = mapper._primary_key_propkeys
if mapper._version_id_prop:
search_keys = {mapper._version_id_prop.key}.union(search_keys)
def _changed_dict(mapper, state):
return dict(
(k, v)
for k, v in state.dict.items()
if k in state.committed_state or k in search_keys
)
if isstates:
if update_changed_only:
mappings = [_changed_dict(mapper, state) for state in mappings]
else:
mappings = [state.dict for state in mappings]
else:
mappings = list(mappings)
if session_transaction.session.connection_callable:
raise NotImplementedError(
"connection_callable / per-instance sharding "
"not supported in bulk_update()"
)
connection = session_transaction.connection(base_mapper)
for table, super_mapper in base_mapper._sorted_tables.items():
if not mapper.isa(super_mapper):
continue
records = _collect_update_commands(
None,
table,
(
(
None,
mapping,
mapper,
connection,
(
mapping[mapper._version_id_prop.key]
if mapper._version_id_prop
else None
),
)
for mapping in mappings
),
bulk=True,
)
_emit_update_statements(
base_mapper,
None,
cached_connections,
super_mapper,
table,
records,
bookkeeping=False,
)
def save_obj(base_mapper, states, uowtransaction, 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, given a list of states to be flushed. The
base mapper in an inheritance hierarchy handles the inserts/
updates for all descendant mappers.
"""
# if batch=false, call _save_obj separately for each object
if not single and not base_mapper.batch:
for state in _sort_states(base_mapper, states):
save_obj(base_mapper, [state], uowtransaction, single=True)
return
states_to_update = []
states_to_insert = []
cached_connections = _cached_connection_dict(base_mapper)
for (
state,
dict_,
mapper,
connection,
has_identity,
row_switch,
update_version_id,
) in _organize_states_for_save(base_mapper, states, uowtransaction):
if has_identity or row_switch:
states_to_update.append(
(state, dict_, mapper, connection, update_version_id)
)
else:
states_to_insert.append((state, dict_, mapper, connection))
for table, mapper in base_mapper._sorted_tables.items():
if table not in mapper._pks_by_table:
continue
insert = _collect_insert_commands(table, states_to_insert)
update = _collect_update_commands(
uowtransaction, table, states_to_update
)
_emit_update_statements(
base_mapper,
uowtransaction,
cached_connections,
mapper,
table,
update,
)
_emit_insert_statements(
base_mapper,
uowtransaction,
cached_connections,
mapper,
table,
insert,
)
_finalize_insert_update_commands(
base_mapper,
uowtransaction,
chain(
(
(state, state_dict, mapper, connection, False)
for (state, state_dict, mapper, connection) in states_to_insert
),
(
(state, state_dict, mapper, connection, True)
for (
state,
state_dict,
mapper,
connection,
update_version_id,
) in states_to_update
),
),
)
def post_update(base_mapper, states, uowtransaction, post_update_cols):
"""Issue UPDATE statements on behalf of a relationship() which
specifies post_update.
"""
cached_connections = _cached_connection_dict(base_mapper)
states_to_update = list(
_organize_states_for_post_update(base_mapper, states, uowtransaction)
)
for table, mapper in base_mapper._sorted_tables.items():
if table not in mapper._pks_by_table:
continue
update = (
(
state,
state_dict,
sub_mapper,
connection,
mapper._get_committed_state_attr_by_column(
state, state_dict, mapper.version_id_col
)
if mapper.version_id_col is not None
else None,
)
for state, state_dict, sub_mapper, connection in states_to_update
if table in sub_mapper._pks_by_table
)
update = _collect_post_update_commands(
base_mapper, uowtransaction, table, update, post_update_cols
)
_emit_post_update_statements(
base_mapper,
uowtransaction,
cached_connections,
mapper,
table,
update,
)
def delete_obj(base_mapper, states, uowtransaction):
"""Issue ``DELETE`` statements for a list of objects.
This is called within the context of a UOWTransaction during a
flush operation.
"""
cached_connections = _cached_connection_dict(base_mapper)
states_to_delete = list(
_organize_states_for_delete(base_mapper, states, uowtransaction)
)
table_to_mapper = base_mapper._sorted_tables
for table in reversed(list(table_to_mapper.keys())):
mapper = table_to_mapper[table]
if table not in mapper._pks_by_table:
continue
elif mapper.inherits and mapper.passive_deletes:
continue
delete = _collect_delete_commands(
base_mapper, uowtransaction, table, states_to_delete
)
_emit_delete_statements(
base_mapper,
uowtransaction,
cached_connections,
mapper,
table,
delete,
)
for (
state,
state_dict,
mapper,
connection,
update_version_id,
) in states_to_delete:
mapper.dispatch.after_delete(mapper, connection, state)
def _organize_states_for_save(base_mapper, states, uowtransaction):
"""Make an initial pass across a set of states for INSERT or
UPDATE.
This includes splitting out into distinct lists for
each, calling before_insert/before_update, obtaining
key information for each state including its dictionary,
mapper, the connection to use for the execution per state,
and the identity flag.
"""
for state, dict_, mapper, connection in _connections_for_states(
base_mapper, uowtransaction, states
):
has_identity = bool(state.key)
instance_key = state.key or mapper._identity_key_from_state(state)
row_switch = update_version_id = None
# call before_XXX extensions
if not has_identity:
mapper.dispatch.before_insert(mapper, connection, state)
else:
mapper.dispatch.before_update(mapper, connection, state)
if mapper._validate_polymorphic_identity:
mapper._validate_polymorphic_identity(mapper, state, dict_)
# 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.was_already_deleted(existing):
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))
)
base_mapper._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
if (has_identity or row_switch) and mapper.version_id_col is not None:
update_version_id = mapper._get_committed_state_attr_by_column(
row_switch if row_switch else state,
row_switch.dict if row_switch else dict_,
mapper.version_id_col,
)
yield (
state,
dict_,
mapper,
connection,
has_identity,
row_switch,
update_version_id,
)
def _organize_states_for_post_update(base_mapper, states, uowtransaction):
"""Make an initial pass across a set of states for UPDATE
corresponding to post_update.
This includes obtaining key information for each state
including its dictionary, mapper, the connection to use for
the execution per state.
"""
return _connections_for_states(base_mapper, uowtransaction, states)
def _organize_states_for_delete(base_mapper, states, uowtransaction):
"""Make an initial pass across a set of states for DELETE.
This includes calling out before_delete and obtaining
key information for each state including its dictionary,
mapper, the connection to use for the execution per state.
"""
for state, dict_, mapper, connection in _connections_for_states(
base_mapper, uowtransaction, states
):
mapper.dispatch.before_delete(mapper, connection, state)
if mapper.version_id_col is not None:
update_version_id = mapper._get_committed_state_attr_by_column(
state, dict_, mapper.version_id_col
)
else:
update_version_id = None
yield (state, dict_, mapper, connection, update_version_id)
def _collect_insert_commands(
table,
states_to_insert,
bulk=False,
return_defaults=False,
render_nulls=False,
):
"""Identify sets of values to use in INSERT statements for a
list of states.
"""
for state, state_dict, mapper, connection in states_to_insert:
if table not in mapper._pks_by_table:
continue
params = {}
value_params = {}
propkey_to_col = mapper._propkey_to_col[table]
eval_none = mapper._insert_cols_evaluating_none[table]
for propkey in set(propkey_to_col).intersection(state_dict):
value = state_dict[propkey]
col = propkey_to_col[propkey]
if value is None and col not in eval_none and not render_nulls:
continue
elif not bulk and (
hasattr(value, "__clause_element__")
or isinstance(value, sql.ClauseElement)
):
value_params[col] = (
value.__clause_element__()
if hasattr(value, "__clause_element__")
else value
)
else:
params[col.key] = value
if not bulk:
# for all the columns that have no default and we don't have
# a value and where "None" is not a special value, add
# explicit None to the INSERT. This is a legacy behavior
# which might be worth removing, as it should not be necessary
# and also produces confusion, given that "missing" and None
# now have distinct meanings
for colkey in (
mapper._insert_cols_as_none[table]
.difference(params)
.difference([c.key for c in value_params])
):
params[colkey] = None
if not bulk or return_defaults:
# params are in terms of Column key objects, so
# compare to pk_keys_by_table
has_all_pks = mapper._pk_keys_by_table[table].issubset(params)
if mapper.base_mapper.eager_defaults:
has_all_defaults = mapper._server_default_cols[table].issubset(
params
)
else:
has_all_defaults = True
else:
has_all_defaults = has_all_pks = True
if (
mapper.version_id_generator is not False
and mapper.version_id_col is not None
and mapper.version_id_col in mapper._cols_by_table[table]
):
params[mapper.version_id_col.key] = mapper.version_id_generator(
None
)
yield (
state,
state_dict,
params,
mapper,
connection,
value_params,
has_all_pks,
has_all_defaults,
)
def _collect_update_commands(
uowtransaction, table, states_to_update, bulk=False
):
"""Identify sets of values to use in UPDATE statements for a
list of states.
This function works intricately with the history system
to determine exactly what values should be updated
as well as how the row should be matched within an UPDATE
statement. Includes some tricky scenarios where the primary
key of an object might have been changed.
"""
for (
state,
state_dict,
mapper,
connection,
update_version_id,
) in states_to_update:
if table not in mapper._pks_by_table:
continue
pks = mapper._pks_by_table[table]
value_params = {}
propkey_to_col = mapper._propkey_to_col[table]
if bulk:
# keys here are mapped attribute keys, so
# look at mapper attribute keys for pk
params = dict(
(propkey_to_col[propkey].key, state_dict[propkey])
for propkey in set(propkey_to_col)
.intersection(state_dict)
.difference(mapper._pk_attr_keys_by_table[table])
)
has_all_defaults = True
else:
params = {}
for propkey in set(propkey_to_col).intersection(
state.committed_state
):
value = state_dict[propkey]
col = propkey_to_col[propkey]
if hasattr(value, "__clause_element__") or isinstance(
value, sql.ClauseElement
):
value_params[col] = (
value.__clause_element__()
if hasattr(value, "__clause_element__")
else value
)
# guard against values that generate non-__nonzero__
# objects for __eq__()
elif (
state.manager[propkey].impl.is_equal(
value, state.committed_state[propkey]
)
is not True
):
params[col.key] = value
if mapper.base_mapper.eager_defaults:
has_all_defaults = (
mapper._server_onupdate_default_cols[table]
).issubset(params)
else:
has_all_defaults = True
if (
update_version_id is not None
and mapper.version_id_col in mapper._cols_by_table[table]
):
if not bulk and not (params or value_params):
# HACK: check for history in other tables, in case the
# history is only in a different table than the one
# where the version_id_col is. This logic was lost
# from 0.9 -> 1.0.0 and restored in 1.0.6.
for prop in mapper._columntoproperty.values():
history = state.manager[prop.key].impl.get_history(
state, state_dict, attributes.PASSIVE_NO_INITIALIZE
)
if history.added:
break
else:
# no net change, break
continue
col = mapper.version_id_col
no_params = not params and not value_params
params[col._label] = update_version_id
if (
bulk or col.key not in params
) and mapper.version_id_generator is not False:
val = mapper.version_id_generator(update_version_id)
params[col.key] = val
elif mapper.version_id_generator is False and no_params:
# no version id generator, no values set on the table,
# and version id wasn't manually incremented.
# set version id to itself so we get an UPDATE
# statement
params[col.key] = update_version_id
elif not (params or value_params):
continue
has_all_pks = True
expect_pk_cascaded = False
if bulk:
# keys here are mapped attribute keys, so
# look at mapper attribute keys for pk
pk_params = dict(
(propkey_to_col[propkey]._label, state_dict.get(propkey))
for propkey in set(propkey_to_col).intersection(
mapper._pk_attr_keys_by_table[table]
)
)
else:
pk_params = {}
for col in pks:
propkey = mapper._columntoproperty[col].key
history = state.manager[propkey].impl.get_history(
state, state_dict, attributes.PASSIVE_OFF
)
if history.added:
if (
not history.deleted
or ("pk_cascaded", state, col)
in uowtransaction.attributes
):
expect_pk_cascaded = True
pk_params[col._label] = history.added[0]
params.pop(col.key, None)
else:
# else, use the old value to locate the row
pk_params[col._label] = history.deleted[0]
if col in value_params:
has_all_pks = False
else:
pk_params[col._label] = history.unchanged[0]
if pk_params[col._label] is None:
raise orm_exc.FlushError(
"Can't update table %s using NULL for primary "
"key value on column %s" % (table, col)
)
if params or value_params:
params.update(pk_params)
yield (
state,
state_dict,
params,
mapper,
connection,
value_params,
has_all_defaults,
has_all_pks,
)
elif expect_pk_cascaded:
# no UPDATE occurs on this table, but we expect that CASCADE rules
# have changed the primary key of the row; propagate this event to
# other columns that expect to have been modified. this normally
# occurs after the UPDATE is emitted however we invoke it here
# explicitly in the absence of our invoking an UPDATE
for m, equated_pairs in mapper._table_to_equated[table]:
sync.populate(
state,
m,
state,
m,
equated_pairs,
uowtransaction,
mapper.passive_updates,
)
def _collect_post_update_commands(
base_mapper, uowtransaction, table, states_to_update, post_update_cols
):
"""Identify sets of values to use in UPDATE statements for a
list of states within a post_update operation.
"""
for (
state,
state_dict,
mapper,
connection,
update_version_id,
) in states_to_update:
# assert table in mapper._pks_by_table
pks = mapper._pks_by_table[table]
params = {}
hasdata = False
for col in mapper._cols_by_table[table]:
if col in pks:
params[col._label] = mapper._get_state_attr_by_column(
state, state_dict, col, passive=attributes.PASSIVE_OFF
)
elif col in post_update_cols or col.onupdate is not None:
prop = mapper._columntoproperty[col]
history = state.manager[prop.key].impl.get_history(
state, state_dict, attributes.PASSIVE_NO_INITIALIZE
)
if history.added:
value = history.added[0]
params[col.key] = value
hasdata = True
if hasdata:
if (
update_version_id is not None
and mapper.version_id_col in mapper._cols_by_table[table]
):
col = mapper.version_id_col
params[col._label] = update_version_id
if (
bool(state.key)
and col.key not in params
and mapper.version_id_generator is not False
):
val = mapper.version_id_generator(update_version_id)
params[col.key] = val
yield state, state_dict, mapper, connection, params
def _collect_delete_commands(
base_mapper, uowtransaction, table, states_to_delete
):
"""Identify values to use in DELETE statements for a list of
states to be deleted."""
for (
state,
state_dict,
mapper,
connection,
update_version_id,
) in states_to_delete:
if table not in mapper._pks_by_table:
continue
params = {}
for col in mapper._pks_by_table[table]:
params[
col.key
] = value = mapper._get_committed_state_attr_by_column(
state, state_dict, col
)
if value is None:
raise orm_exc.FlushError(
"Can't delete from table %s "
"using NULL for primary "
"key value on column %s" % (table, col)
)
if (
update_version_id is not None
and mapper.version_id_col in mapper._cols_by_table[table]
):
params[mapper.version_id_col.key] = update_version_id
yield params, connection
def _emit_update_statements(
base_mapper,
uowtransaction,
cached_connections,
mapper,
table,
update,
bookkeeping=True,
):
"""Emit UPDATE statements corresponding to value lists collected
by _collect_update_commands()."""
needs_version_id = (
mapper.version_id_col is not None
and mapper.version_id_col in mapper._cols_by_table[table]
)
def update_stmt():
clause = sql.and_()
for col in mapper._pks_by_table[table]:
clause.clauses.append(
col == sql.bindparam(col._label, type_=col.type)
)
if needs_version_id:
clause.clauses.append(
mapper.version_id_col
== sql.bindparam(
mapper.version_id_col._label,
type_=mapper.version_id_col.type,
)
)
stmt = table.update(clause)
return stmt
cached_stmt = base_mapper._memo(("update", table), update_stmt)
for (
(connection, paramkeys, hasvalue, has_all_defaults, has_all_pks),
records,
) in groupby(
update,
lambda rec: (
rec[4], # connection
set(rec[2]), # set of parameter keys
bool(rec[5]), # whether or not we have "value" parameters
rec[6], # has_all_defaults
rec[7], # has all pks
),
):
rows = 0
records = list(records)
statement = cached_stmt
return_defaults = False
if not has_all_pks:
statement = statement.return_defaults()
return_defaults = True
elif (
bookkeeping
and not has_all_defaults
and mapper.base_mapper.eager_defaults
):
statement = statement.return_defaults()
return_defaults = True
elif mapper.version_id_col is not None:
statement = statement.return_defaults(mapper.version_id_col)
return_defaults = True
assert_singlerow = (
connection.dialect.supports_sane_rowcount
if not return_defaults
else connection.dialect.supports_sane_rowcount_returning
)
assert_multirow = (
assert_singlerow
and connection.dialect.supports_sane_multi_rowcount
)
allow_multirow = has_all_defaults and not needs_version_id
if hasvalue:
for (
state,
state_dict,
params,
mapper,
connection,
value_params,
has_all_defaults,
has_all_pks,
) in records:
c = connection.execute(statement.values(value_params), params)
if bookkeeping:
_postfetch(
mapper,
uowtransaction,
table,
state,
state_dict,
c,
c.context.compiled_parameters[0],
value_params,
True,
)
rows += c.rowcount
check_rowcount = assert_singlerow
else:
if not allow_multirow:
check_rowcount = assert_singlerow
for (
state,
state_dict,
params,
mapper,
connection,
value_params,
has_all_defaults,
has_all_pks,
) in records:
c = cached_connections[connection].execute(
statement, params
)
# TODO: why with bookkeeping=False?
if bookkeeping:
_postfetch(
mapper,
uowtransaction,
table,
state,
state_dict,
c,
c.context.compiled_parameters[0],
value_params,
True,
)
rows += c.rowcount
else:
multiparams = [rec[2] for rec in records]
check_rowcount = assert_multirow or (
assert_singlerow and len(multiparams) == 1
)
c = cached_connections[connection].execute(
statement, multiparams
)
rows += c.rowcount
for (
state,
state_dict,
params,
mapper,
connection,
value_params,
has_all_defaults,
has_all_pks,
) in records:
if bookkeeping:
_postfetch(
mapper,
uowtransaction,
table,
state,
state_dict,
c,
c.context.compiled_parameters[0],
value_params,
True,
)
if check_rowcount:
if rows != len(records):
raise orm_exc.StaleDataError(
"UPDATE statement on table '%s' expected to "
"update %d row(s); %d were matched."
% (table.description, len(records), rows)
)
elif needs_version_id:
util.warn(
"Dialect %s does not support updated rowcount "
"- versioning cannot be verified."
% c.dialect.dialect_description
)
def _emit_insert_statements(
base_mapper,
uowtransaction,
cached_connections,
mapper,
table,
insert,
bookkeeping=True,
):
"""Emit INSERT statements corresponding to value lists collected
by _collect_insert_commands()."""
cached_stmt = base_mapper._memo(("insert", table), table.insert)
for (
(connection, pkeys, hasvalue, has_all_pks, has_all_defaults),
records,
) in groupby(
insert,
lambda rec: (
rec[4], # connection
set(rec[2]), # parameter keys
bool(rec[5]), # whether we have "value" parameters
rec[6],
rec[7],
),
):
statement = cached_stmt
if (
not bookkeeping
or (
has_all_defaults
or not base_mapper.eager_defaults
or not connection.dialect.implicit_returning
)
and has_all_pks
and not hasvalue
):
records = list(records)
multiparams = [rec[2] for rec in records]
c = cached_connections[connection].execute(statement, multiparams)
if bookkeeping:
for (
(
state,
state_dict,
params,
mapper_rec,
conn,
value_params,
has_all_pks,
has_all_defaults,
),
last_inserted_params,
) in zip(records, c.context.compiled_parameters):
if state:
_postfetch(
mapper_rec,
uowtransaction,
table,
state,
state_dict,
c,
last_inserted_params,
value_params,
False,
)
else:
_postfetch_bulk_save(mapper_rec, state_dict, table)
else:
if not has_all_defaults and base_mapper.eager_defaults:
statement = statement.return_defaults()
elif mapper.version_id_col is not None:
statement = statement.return_defaults(mapper.version_id_col)
for (
state,
state_dict,
params,
mapper_rec,
connection,
value_params,
has_all_pks,
has_all_defaults,
) in records:
if value_params:
result = connection.execute(
statement.values(value_params), params
)
else:
result = cached_connections[connection].execute(
statement, params
)
primary_key = result.context.inserted_primary_key
if primary_key is not None:
# set primary key attributes
for pk, col in zip(
primary_key, mapper._pks_by_table[table]
):
prop = mapper_rec._columntoproperty[col]
if pk is not None and (
col in value_params
or state_dict.get(prop.key) is None
):
state_dict[prop.key] = pk
if bookkeeping:
if state:
_postfetch(
mapper_rec,
uowtransaction,
table,
state,
state_dict,
result,
result.context.compiled_parameters[0],
value_params,
False,
)
else:
_postfetch_bulk_save(mapper_rec, state_dict, table)
def _emit_post_update_statements(
base_mapper, uowtransaction, cached_connections, mapper, table, update
):
"""Emit UPDATE statements corresponding to value lists collected
by _collect_post_update_commands()."""
needs_version_id = (
mapper.version_id_col is not None
and mapper.version_id_col in mapper._cols_by_table[table]
)
def update_stmt():
clause = sql.and_()
for col in mapper._pks_by_table[table]:
clause.clauses.append(
col == sql.bindparam(col._label, type_=col.type)
)
if needs_version_id:
clause.clauses.append(
mapper.version_id_col
== sql.bindparam(
mapper.version_id_col._label,
type_=mapper.version_id_col.type,
)
)
stmt = table.update(clause)
if mapper.version_id_col is not None:
stmt = stmt.return_defaults(mapper.version_id_col)
return stmt
statement = base_mapper._memo(("post_update", table), update_stmt)
# execute each UPDATE in the order according to the original
# list of states to guarantee row access order, but
# also group them into common (connection, cols) sets
# to support executemany().
for key, records in groupby(
update,
lambda rec: (rec[3], set(rec[4])), # connection # parameter keys
):
rows = 0
records = list(records)
connection = key[0]
assert_singlerow = (
connection.dialect.supports_sane_rowcount
if mapper.version_id_col is None
else connection.dialect.supports_sane_rowcount_returning
)
assert_multirow = (
assert_singlerow
and connection.dialect.supports_sane_multi_rowcount
)
allow_multirow = not needs_version_id or assert_multirow
if not allow_multirow:
check_rowcount = assert_singlerow
for state, state_dict, mapper_rec, connection, params in records:
c = cached_connections[connection].execute(statement, params)
_postfetch_post_update(
mapper_rec,
uowtransaction,
table,
state,
state_dict,
c,
c.context.compiled_parameters[0],
)
rows += c.rowcount
else:
multiparams = [
params
for state, state_dict, mapper_rec, conn, params in records
]
check_rowcount = assert_multirow or (
assert_singlerow and len(multiparams) == 1
)
c = cached_connections[connection].execute(statement, multiparams)
rows += c.rowcount
for state, state_dict, mapper_rec, connection, params in records:
_postfetch_post_update(
mapper_rec,
uowtransaction,
table,
state,
state_dict,
c,
c.context.compiled_parameters[0],
)
if check_rowcount:
if rows != len(records):
raise orm_exc.StaleDataError(
"UPDATE statement on table '%s' expected to "
"update %d row(s); %d were matched."
% (table.description, len(records), rows)
)
elif needs_version_id:
util.warn(
"Dialect %s does not support updated rowcount "
"- versioning cannot be verified."
% c.dialect.dialect_description
)
def _emit_delete_statements(
base_mapper, uowtransaction, cached_connections, mapper, table, delete
):
"""Emit DELETE statements corresponding to value lists collected
by _collect_delete_commands()."""
need_version_id = (
mapper.version_id_col is not None
and mapper.version_id_col in mapper._cols_by_table[table]
)
def delete_stmt():
clause = sql.and_()
for col in mapper._pks_by_table[table]:
clause.clauses.append(
col == sql.bindparam(col.key, type_=col.type)
)
if need_version_id:
clause.clauses.append(
mapper.version_id_col
== sql.bindparam(
mapper.version_id_col.key, type_=mapper.version_id_col.type
)
)
return table.delete(clause)
statement = base_mapper._memo(("delete", table), delete_stmt)
for connection, recs in groupby(delete, lambda rec: rec[1]): # connection
del_objects = [params for params, connection in recs]
connection = cached_connections[connection]
expected = len(del_objects)
rows_matched = -1
only_warn = False
if (
need_version_id
and not connection.dialect.supports_sane_multi_rowcount
):
if connection.dialect.supports_sane_rowcount:
rows_matched = 0
# execute deletes individually so that versioned
# rows can be verified
for params in del_objects:
c = connection.execute(statement, params)
rows_matched += c.rowcount
else:
util.warn(
"Dialect %s does not support deleted rowcount "
"- versioning cannot be verified."
% connection.dialect.dialect_description
)
connection.execute(statement, del_objects)
else:
c = connection.execute(statement, del_objects)
if not need_version_id:
only_warn = True
rows_matched = c.rowcount
if (
base_mapper.confirm_deleted_rows
and rows_matched > -1
and expected != rows_matched
and (
connection.dialect.supports_sane_multi_rowcount
or len(del_objects) == 1
)
):
# TODO: why does this "only warn" if versioning is turned off,
# whereas the UPDATE raises?
if only_warn:
util.warn(
"DELETE statement on table '%s' expected to "
"delete %d row(s); %d were matched. Please set "
"confirm_deleted_rows=False within the mapper "
"configuration to prevent this warning."
% (table.description, expected, rows_matched)
)
else:
raise orm_exc.StaleDataError(
"DELETE statement on table '%s' expected to "
"delete %d row(s); %d were matched. Please set "
"confirm_deleted_rows=False within the mapper "
"configuration to prevent this warning."
% (table.description, expected, rows_matched)
)
def _finalize_insert_update_commands(base_mapper, uowtransaction, states):
"""finalize state on states that have been inserted or updated,
including calling after_insert/after_update events.
"""
for state, state_dict, mapper, connection, has_identity in states:
if mapper._readonly_props:
readonly = state.unmodified_intersection(
[
p.key
for p in mapper._readonly_props
if (
p.expire_on_flush
and (not p.deferred or p.key in state.dict)
)
or (
not p.expire_on_flush
and not p.deferred
and p.key not in state.dict
)
]
)
if readonly:
state._expire_attributes(state.dict, readonly)
# if eager_defaults option is enabled, load
# all expired cols. Else if we have a version_id_col, make sure
# it isn't expired.
toload_now = []
if base_mapper.eager_defaults:
toload_now.extend(
state._unloaded_non_object.intersection(
mapper._server_default_plus_onupdate_propkeys
)
)
if (
mapper.version_id_col is not None
and mapper.version_id_generator is False
):
if mapper._version_id_prop.key in state.unloaded:
toload_now.extend([mapper._version_id_prop.key])
if toload_now:
state.key = base_mapper._identity_key_from_state(state)
loading.load_on_ident(
uowtransaction.session.query(mapper),
state.key,
refresh_state=state,
only_load_props=toload_now,
)
# call after_XXX extensions
if not has_identity:
mapper.dispatch.after_insert(mapper, connection, state)
else:
mapper.dispatch.after_update(mapper, connection, state)
if (
mapper.version_id_generator is False
and mapper.version_id_col is not None
):
if state_dict[mapper._version_id_prop.key] is None:
raise orm_exc.FlushError(
"Instance does not contain a non-NULL version value"
)
def _postfetch_post_update(
mapper, uowtransaction, table, state, dict_, result, params
):
if uowtransaction.is_deleted(state):
return
prefetch_cols = result.context.compiled.prefetch
postfetch_cols = result.context.compiled.postfetch
if (
mapper.version_id_col is not None
and mapper.version_id_col in mapper._cols_by_table[table]
):
prefetch_cols = list(prefetch_cols) + [mapper.version_id_col]
refresh_flush = bool(mapper.class_manager.dispatch.refresh_flush)
if refresh_flush:
load_evt_attrs = []
for c in prefetch_cols:
if c.key in params and c in mapper._columntoproperty:
dict_[mapper._columntoproperty[c].key] = params[c.key]
if refresh_flush:
load_evt_attrs.append(mapper._columntoproperty[c].key)
if refresh_flush and load_evt_attrs:
mapper.class_manager.dispatch.refresh_flush(
state, uowtransaction, load_evt_attrs
)
if postfetch_cols:
state._expire_attributes(
state.dict,
[
mapper._columntoproperty[c].key
for c in postfetch_cols
if c in mapper._columntoproperty
],
)
def _postfetch(
mapper,
uowtransaction,
table,
state,
dict_,
result,
params,
value_params,
isupdate,
):
"""Expire attributes in need of newly persisted database state,
after an INSERT or UPDATE statement has proceeded for that
state."""
prefetch_cols = result.context.compiled.prefetch
postfetch_cols = result.context.compiled.postfetch
returning_cols = result.context.compiled.returning
if (
mapper.version_id_col is not None
and mapper.version_id_col in mapper._cols_by_table[table]
):
prefetch_cols = list(prefetch_cols) + [mapper.version_id_col]
refresh_flush = bool(mapper.class_manager.dispatch.refresh_flush)
if refresh_flush:
load_evt_attrs = []
if returning_cols:
row = result.context.returned_defaults
if row is not None:
for col in returning_cols:
# pk cols returned from insert are handled
# distinctly, don't step on the values here
if col.primary_key and result.context.isinsert:
continue
# note that columns can be in the "return defaults" that are
# not mapped to this mapper, typically because they are
# "excluded", which can be specified directly or also occurs
# when using declarative w/ single table inheritance
prop = mapper._columntoproperty.get(col)
if prop:
dict_[prop.key] = row[col]
if refresh_flush:
load_evt_attrs.append(prop.key)
for c in prefetch_cols:
if c.key in params and c in mapper._columntoproperty:
dict_[mapper._columntoproperty[c].key] = params[c.key]
if refresh_flush:
load_evt_attrs.append(mapper._columntoproperty[c].key)
if refresh_flush and load_evt_attrs:
mapper.class_manager.dispatch.refresh_flush(
state, uowtransaction, load_evt_attrs
)
if isupdate and value_params:
# explicitly suit the use case specified by
# [ticket:3801], PK SQL expressions for UPDATE on non-RETURNING
# database which are set to themselves in order to do a version bump.
postfetch_cols.extend(
[
col
for col in value_params
if col.primary_key and col not in returning_cols
]
)
if postfetch_cols:
state._expire_attributes(
state.dict,
[
mapper._columntoproperty[c].key
for c in postfetch_cols
if c in mapper._columntoproperty
],
)
# 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 mapper._table_to_equated[table]:
sync.populate(
state,
m,
state,
m,
equated_pairs,
uowtransaction,
mapper.passive_updates,
)
def _postfetch_bulk_save(mapper, dict_, table):
for m, equated_pairs in mapper._table_to_equated[table]:
sync.bulk_populate_inherit_keys(dict_, m, equated_pairs)
def _connections_for_states(base_mapper, uowtransaction, states):
"""Return an iterator of (state, state.dict, mapper, connection).
The states are sorted according to _sort_states, then paired
with the connection they should be using for the given
unit of work transaction.
"""
# if session has a connection callable,
# organize individual states with the connection
# to use for update
if uowtransaction.session.connection_callable:
connection_callable = uowtransaction.session.connection_callable
else:
connection = uowtransaction.transaction.connection(base_mapper)
connection_callable = None
for state in _sort_states(base_mapper, states):
if connection_callable:
connection = connection_callable(base_mapper, state.obj())
mapper = state.manager.mapper
yield state, state.dict, mapper, connection
def _cached_connection_dict(base_mapper):
# dictionary of connection->connection_with_cache_options.
return util.PopulateDict(
lambda conn: conn.execution_options(
compiled_cache=base_mapper._compiled_cache
)
)
def _sort_states(mapper, states):
pending = set(states)
persistent = set(s for s in pending if s.key is not None)
pending.difference_update(persistent)
try:
persistent_sorted = sorted(
persistent, key=mapper._persistent_sortkey_fn
)
except TypeError as err:
util.raise_(
sa_exc.InvalidRequestError(
"Could not sort objects by primary key; primary key "
"values must be sortable in Python (was: %s)" % err
),
replace_context=err,
)
return (
sorted(pending, key=operator.attrgetter("insert_order"))
+ persistent_sorted
)
class BulkUD(object):
"""Handle bulk update and deletes via a :class:`_query.Query`."""
def __init__(self, query):
self.query = query.enable_eagerloads(False)
self.mapper = self.query._bind_mapper()
self._validate_query_state()
def _validate_query_state(self):
for attr, methname, notset, op in (
("_limit", "limit()", None, operator.is_),
("_offset", "offset()", None, operator.is_),
("_order_by", "order_by()", False, operator.is_),
("_group_by", "group_by()", False, operator.is_),
("_distinct", "distinct()", False, operator.is_),
(
"_from_obj",
"join(), outerjoin(), select_from(), or from_self()",
(),
operator.eq,
),
):
if not op(getattr(self.query, attr), notset):
raise sa_exc.InvalidRequestError(
"Can't call Query.update() or Query.delete() "
"when %s has been called" % (methname,)
)
@property
def session(self):
return self.query.session
@classmethod
def _factory(cls, lookup, synchronize_session, *arg):
try:
klass = lookup[synchronize_session]
except KeyError as err:
util.raise_(
sa_exc.ArgumentError(
"Valid strategies for session synchronization "
"are %s" % (", ".join(sorted(repr(x) for x in lookup)))
),
replace_context=err,
)
else:
return klass(*arg)
def exec_(self):
self._do_before_compile()
self._do_pre()
self._do_pre_synchronize()
self._do_exec()
self._do_post_synchronize()
self._do_post()
def _execute_stmt(self, stmt):
self.result = self.query._execute_crud(stmt, self.mapper)
self.rowcount = self.result.rowcount
def _do_before_compile(self):
raise NotImplementedError()
@util.dependencies("sqlalchemy.orm.query")
def _do_pre(self, querylib):
query = self.query
self.context = querylib.QueryContext(query)
if isinstance(query._entities[0], querylib._ColumnEntity):
# check for special case of query(table)
tables = set()
for ent in query._entities:
if not isinstance(ent, querylib._ColumnEntity):
tables.clear()
break
else:
tables.update(_from_objects(ent.column))
if len(tables) != 1:
raise sa_exc.InvalidRequestError(
"This operation requires only one Table or "
"entity be specified as the target."
)
else:
self.primary_table = tables.pop()
else:
self.primary_table = query._only_entity_zero(
"This operation requires only one Table or "
"entity be specified as the target."
).mapper.local_table
session = query.session
if query._autoflush:
session._autoflush()
def _do_pre_synchronize(self):
pass
def _do_post_synchronize(self):
pass
class BulkEvaluate(BulkUD):
"""BulkUD which does the 'evaluate' method of session state resolution."""
def _additional_evaluators(self, evaluator_compiler):
pass
def _do_pre_synchronize(self):
query = self.query
target_cls = query._mapper_zero().class_
try:
evaluator_compiler = evaluator.EvaluatorCompiler(target_cls)
if query.whereclause is not None:
eval_condition = evaluator_compiler.process(query.whereclause)
else:
def eval_condition(obj):
return True
self._additional_evaluators(evaluator_compiler)
except evaluator.UnevaluatableError as err:
util.raise_(
sa_exc.InvalidRequestError(
'Could not evaluate current criteria in Python: "%s". '
"Specify 'fetch' or False for the "
"synchronize_session parameter." % err
),
from_=err,
)
# TODO: detect when the where clause is a trivial primary key match
self.matched_objects = [
obj
for (
cls,
pk,
identity_token,
), obj in query.session.identity_map.items()
if issubclass(cls, target_cls)
and not attributes.instance_state(obj).expired
and eval_condition(obj)
]
class BulkFetch(BulkUD):
"""BulkUD which does the 'fetch' method of session state resolution."""
def _do_pre_synchronize(self):
query = self.query
session = query.session
context = query._compile_context()
select_stmt = context.statement.with_only_columns(
self.primary_table.primary_key
)
self.matched_rows = session.execute(
select_stmt, mapper=self.mapper, params=query._params
).fetchall()
class BulkUpdate(BulkUD):
"""BulkUD which handles UPDATEs."""
def __init__(self, query, values, update_kwargs):
super(BulkUpdate, self).__init__(query)
self.values = values
self.update_kwargs = update_kwargs
@classmethod
def factory(cls, query, synchronize_session, values, update_kwargs):
return BulkUD._factory(
{
"evaluate": BulkUpdateEvaluate,
"fetch": BulkUpdateFetch,
False: BulkUpdate,
},
synchronize_session,
query,
values,
update_kwargs,
)
def _do_before_compile(self):
if self.query.dispatch.before_compile_update:
for fn in self.query.dispatch.before_compile_update:
new_query = fn(self.query, self)
if new_query is not None:
self.query = new_query
@property
def _resolved_values(self):
values = []
for k, v in (
self.values.items()
if hasattr(self.values, "items")
else self.values
):
if self.mapper:
if isinstance(k, util.string_types):
desc = _entity_descriptor(self.mapper, k)
values.extend(desc._bulk_update_tuples(v))
elif isinstance(k, attributes.QueryableAttribute):
values.extend(k._bulk_update_tuples(v))
else:
values.append((k, v))
else:
values.append((k, v))
return values
@property
def _resolved_values_keys_as_propnames(self):
values = []
for k, v in self._resolved_values:
if isinstance(k, attributes.QueryableAttribute):
values.append((k.key, v))
continue
elif hasattr(k, "__clause_element__"):
k = k.__clause_element__()
if self.mapper and isinstance(k, expression.ColumnElement):
try:
attr = self.mapper._columntoproperty[k]
except orm_exc.UnmappedColumnError:
pass
else:
values.append((attr.key, v))
else:
raise sa_exc.InvalidRequestError(
"Invalid expression type: %r" % k
)
return values
def _do_exec(self):
values = self._resolved_values
if not self.update_kwargs.get("preserve_parameter_order", False):
values = dict(values)
update_stmt = sql.update(
self.primary_table,
self.context.whereclause,
values,
**self.update_kwargs
)
self._execute_stmt(update_stmt)
def _do_post(self):
session = self.query.session
session.dispatch.after_bulk_update(self)
class BulkDelete(BulkUD):
"""BulkUD which handles DELETEs."""
def __init__(self, query):
super(BulkDelete, self).__init__(query)
@classmethod
def factory(cls, query, synchronize_session):
return BulkUD._factory(
{
"evaluate": BulkDeleteEvaluate,
"fetch": BulkDeleteFetch,
False: BulkDelete,
},
synchronize_session,
query,
)
def _do_before_compile(self):
if self.query.dispatch.before_compile_delete:
for fn in self.query.dispatch.before_compile_delete:
new_query = fn(self.query, self)
if new_query is not None:
self.query = new_query
def _do_exec(self):
delete_stmt = sql.delete(self.primary_table, self.context.whereclause)
self._execute_stmt(delete_stmt)
def _do_post(self):
session = self.query.session
session.dispatch.after_bulk_delete(self)
class BulkUpdateEvaluate(BulkEvaluate, BulkUpdate):
"""BulkUD which handles UPDATEs using the "evaluate"
method of session resolution."""
def _additional_evaluators(self, evaluator_compiler):
self.value_evaluators = {}
values = self._resolved_values_keys_as_propnames
for key, value in values:
self.value_evaluators[key] = evaluator_compiler.process(
expression._literal_as_binds(value)
)
def _do_post_synchronize(self):
session = self.query.session
states = set()
evaluated_keys = list(self.value_evaluators.keys())
for obj in self.matched_objects:
state, dict_ = (
attributes.instance_state(obj),
attributes.instance_dict(obj),
)
# only evaluate unmodified attributes
to_evaluate = state.unmodified.intersection(evaluated_keys)
for key in to_evaluate:
if key in dict_:
dict_[key] = self.value_evaluators[key](obj)
state.manager.dispatch.refresh(state, None, to_evaluate)
state._commit(dict_, list(to_evaluate))
# expire attributes with pending changes
# (there was no autoflush, so they are overwritten)
state._expire_attributes(
dict_, set(evaluated_keys).difference(to_evaluate)
)
states.add(state)
session._register_altered(states)
class BulkDeleteEvaluate(BulkEvaluate, BulkDelete):
"""BulkUD which handles DELETEs using the "evaluate"
method of session resolution."""
def _do_post_synchronize(self):
self.query.session._remove_newly_deleted(
[attributes.instance_state(obj) for obj in self.matched_objects]
)
class BulkUpdateFetch(BulkFetch, BulkUpdate):
"""BulkUD which handles UPDATEs using the "fetch"
method of session resolution."""
def _do_post_synchronize(self):
session = self.query.session
target_mapper = self.query._mapper_zero()
states = set(
[
attributes.instance_state(session.identity_map[identity_key])
for identity_key in [
target_mapper.identity_key_from_primary_key(
list(primary_key)
)
for primary_key in self.matched_rows
]
if identity_key in session.identity_map
]
)
values = self._resolved_values_keys_as_propnames
attrib = set(k for k, v in values)
for state in states:
to_expire = attrib.intersection(state.dict)
if to_expire:
session._expire_state(state, to_expire)
session._register_altered(states)
class BulkDeleteFetch(BulkFetch, BulkDelete):
"""BulkUD which handles DELETEs using the "fetch"
method of session resolution."""
def _do_post_synchronize(self):
session = self.query.session
target_mapper = self.query._mapper_zero()
for primary_key in self.matched_rows:
# TODO: inline this and call remove_newly_deleted
# once
identity_key = target_mapper.identity_key_from_primary_key(
list(primary_key)
)
if identity_key in session.identity_map:
session._remove_newly_deleted(
[
attributes.instance_state(
session.identity_map[identity_key]
)
]
)
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