JezK
Edit File: sync.py
# orm/sync.py # Copyright (C) 2005-2024 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: https://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, )