You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
97 lines
4.3 KiB
97 lines
4.3 KiB
# orm/sync.py
|
|
# Copyright (C) 2005-2011 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 for copying data
|
|
between instances based on join conditions.
|
|
"""
|
|
|
|
from sqlalchemy.orm import exc, util as mapperutil
|
|
|
|
def populate(source, source_mapper, dest, dest_mapper,
|
|
synchronize_pairs, uowcommit, flag_cascaded_pks):
|
|
for l, r in synchronize_pairs:
|
|
try:
|
|
value = source_mapper._get_state_attr_by_column(source, source.dict, l)
|
|
except exc.UnmappedColumnError:
|
|
_raise_col_to_prop(False, source_mapper, l, dest_mapper, r)
|
|
|
|
try:
|
|
dest_mapper._set_state_attr_by_column(dest, dest.dict, r, value)
|
|
except exc.UnmappedColumnError:
|
|
_raise_col_to_prop(True, source_mapper, l, dest_mapper, r)
|
|
|
|
# techically the "r.primary_key" check isn't
|
|
# needed here, but we check for this condition to limit
|
|
# how often this logic is invoked for memory/performance
|
|
# reasons, since we only need this info for a primary key
|
|
# destination.
|
|
if l.primary_key and r.primary_key and \
|
|
r.references(l) and flag_cascaded_pks:
|
|
uowcommit.attributes[("pk_cascaded", dest, r)] = True
|
|
|
|
def clear(dest, dest_mapper, synchronize_pairs):
|
|
for l, r in synchronize_pairs:
|
|
if r.primary_key:
|
|
raise AssertionError(
|
|
"Dependency rule tried to blank-out primary key "
|
|
"column '%s' on instance '%s'" %
|
|
(r, mapperutil.state_str(dest))
|
|
)
|
|
try:
|
|
dest_mapper._set_state_attr_by_column(dest, dest.dict, r, None)
|
|
except exc.UnmappedColumnError:
|
|
_raise_col_to_prop(True, None, l, dest_mapper, r)
|
|
|
|
def update(source, source_mapper, dest, old_prefix, synchronize_pairs):
|
|
for l, r in synchronize_pairs:
|
|
try:
|
|
oldvalue = source_mapper._get_committed_attr_by_column(source.obj(), l)
|
|
value = source_mapper._get_state_attr_by_column(source, source.dict, l)
|
|
except exc.UnmappedColumnError:
|
|
_raise_col_to_prop(False, source_mapper, l, None, r)
|
|
dest[r.key] = value
|
|
dest[old_prefix + r.key] = oldvalue
|
|
|
|
def populate_dict(source, source_mapper, dict_, synchronize_pairs):
|
|
for l, r in synchronize_pairs:
|
|
try:
|
|
value = source_mapper._get_state_attr_by_column(source, source.dict, l)
|
|
except exc.UnmappedColumnError:
|
|
_raise_col_to_prop(False, source_mapper, l, None, r)
|
|
|
|
dict_[r.key] = value
|
|
|
|
def source_modified(uowcommit, source, source_mapper, synchronize_pairs):
|
|
"""return true if the source object has changes from an old to a
|
|
new value on the given synchronize pairs
|
|
|
|
"""
|
|
for l, r in synchronize_pairs:
|
|
try:
|
|
prop = source_mapper._columntoproperty[l]
|
|
except exc.UnmappedColumnError:
|
|
_raise_col_to_prop(False, source_mapper, l, None, r)
|
|
history = uowcommit.get_attribute_history(source, prop.key, passive=True)
|
|
return bool(history.deleted)
|
|
else:
|
|
return False
|
|
|
|
def _raise_col_to_prop(isdest, source_mapper, source_column, dest_mapper, dest_column):
|
|
if isdest:
|
|
raise exc.UnmappedColumnError(
|
|
"Can't execute sync rule for destination column '%s'; "
|
|
"mapper '%s' does not map this column. Try using an explicit"
|
|
" `foreign_keys` collection which does not include this column "
|
|
"(or use a viewonly=True relation)." % (dest_column, source_mapper)
|
|
)
|
|
else:
|
|
raise exc.UnmappedColumnError(
|
|
"Can't execute sync rule for source column '%s'; mapper '%s' "
|
|
"does not map this column. Try using an explicit `foreign_keys`"
|
|
" collection which does not include destination column '%s' (or "
|
|
"use a viewonly=True relation)." %
|
|
(source_column, source_mapper, dest_column)
|
|
)
|
|
|