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persistence.py
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# orm/persistence.py # Copyright (C) 2005-2019 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:`.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(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, stacklevel=12, ) 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(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(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=lambda q: q.key[1]) except TypeError as err: raise sa_exc.InvalidRequestError( "Could not sort objects by primary key; primary key " "values must be sortable in Python (was: %s)" % err ) return ( sorted(pending, key=operator.attrgetter("insert_order")) + persistent_sorted ) class BulkUD(object): """Handle bulk update and deletes via a :class:`.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: raise sa_exc.ArgumentError( "Valid strategies for session synchronization " "are %s" % (", ".join(sorted(repr(x) for x in lookup))) ) 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: raise sa_exc.InvalidRequestError( 'Could not evaluate current criteria in Python: "%s". ' "Specify 'fetch' or False for the " "synchronize_session parameter." % 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 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: 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] ) ] )