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Diffstat (limited to 'lib/sqlalchemy/orm/sync.py')
| -rw-r--r-- | lib/sqlalchemy/orm/sync.py | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/lib/sqlalchemy/orm/sync.py b/lib/sqlalchemy/orm/sync.py new file mode 100644 index 0000000..c041804 --- /dev/null +++ b/lib/sqlalchemy/orm/sync.py @@ -0,0 +1,167 @@ +# orm/sync.py +# Copyright (C) 2005-2022 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, + ) |