|
- # orm/sync.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 for copying data
- between instances based on join conditions.
-
- """
-
- from . import attributes
- from . import exc
- from . import util as orm_util
- from .. import util
-
-
- def populate(
- source,
- source_mapper,
- dest,
- dest_mapper,
- synchronize_pairs,
- uowcommit,
- flag_cascaded_pks,
- ):
- source_dict = source.dict
- dest_dict = dest.dict
-
- for l, r in synchronize_pairs:
- try:
- # inline of source_mapper._get_state_attr_by_column
- prop = source_mapper._columntoproperty[l]
- value = source.manager[prop.key].impl.get(
- source, source_dict, attributes.PASSIVE_OFF
- )
- except exc.UnmappedColumnError as err:
- _raise_col_to_prop(False, source_mapper, l, dest_mapper, r, err)
-
- try:
- # inline of dest_mapper._set_state_attr_by_column
- prop = dest_mapper._columntoproperty[r]
- dest.manager[prop.key].impl.set(dest, dest_dict, value, None)
- except exc.UnmappedColumnError as err:
- _raise_col_to_prop(True, source_mapper, l, dest_mapper, r, err)
-
- # technically 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 (
- flag_cascaded_pks
- and l.primary_key
- and r.primary_key
- and r.references(l)
- ):
- uowcommit.attributes[("pk_cascaded", dest, r)] = True
-
-
- def bulk_populate_inherit_keys(source_dict, source_mapper, synchronize_pairs):
- # a simplified version of populate() used by bulk insert mode
- for l, r in synchronize_pairs:
- try:
- prop = source_mapper._columntoproperty[l]
- value = source_dict[prop.key]
- except exc.UnmappedColumnError as err:
- _raise_col_to_prop(False, source_mapper, l, source_mapper, r, err)
-
- try:
- prop = source_mapper._columntoproperty[r]
- source_dict[prop.key] = value
- except exc.UnmappedColumnError:
- _raise_col_to_prop(True, source_mapper, l, source_mapper, r)
-
-
- def clear(dest, dest_mapper, synchronize_pairs):
- for l, r in synchronize_pairs:
- if (
- r.primary_key
- and dest_mapper._get_state_attr_by_column(dest, dest.dict, r)
- not in orm_util._none_set
- ):
-
- raise AssertionError(
- "Dependency rule tried to blank-out primary key "
- "column '%s' on instance '%s'" % (r, orm_util.state_str(dest))
- )
- try:
- dest_mapper._set_state_attr_by_column(dest, dest.dict, r, None)
- except exc.UnmappedColumnError as err:
- _raise_col_to_prop(True, None, l, dest_mapper, r, err)
-
-
- 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, passive=attributes.PASSIVE_OFF
- )
- except exc.UnmappedColumnError as err:
- _raise_col_to_prop(False, source_mapper, l, None, r, err)
- 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, passive=attributes.PASSIVE_OFF
- )
- except exc.UnmappedColumnError as err:
- _raise_col_to_prop(False, source_mapper, l, None, r, err)
-
- 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 as err:
- _raise_col_to_prop(False, source_mapper, l, None, r, err)
- history = uowcommit.get_attribute_history(
- source, prop.key, attributes.PASSIVE_NO_INITIALIZE
- )
- if bool(history.deleted):
- return True
- else:
- return False
-
-
- def _raise_col_to_prop(
- isdest, source_mapper, source_column, dest_mapper, dest_column, err
- ):
- if isdest:
- util.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, dest_mapper)
- ),
- replace_context=err,
- )
- else:
- util.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)
- ),
- replace_context=err,
- )
|