diff options
Diffstat (limited to 'lib/sqlalchemy/orm/loading.py')
| -rw-r--r-- | lib/sqlalchemy/orm/loading.py | 111 |
1 files changed, 60 insertions, 51 deletions
diff --git a/lib/sqlalchemy/orm/loading.py b/lib/sqlalchemy/orm/loading.py index d3d170d94..781a96a5e 100644 --- a/lib/sqlalchemy/orm/loading.py +++ b/lib/sqlalchemy/orm/loading.py @@ -304,6 +304,9 @@ def instance_processor(mapper, context, result, path, adapter, def _instance(row): + # if we are doing polymorphic, dispatch + # to a different _instance() method specific to + # the subclass mapper if polymorphic_on is not None: discriminator = row[polymorphic_on] if discriminator is not None: @@ -311,43 +314,9 @@ def instance_processor(mapper, context, result, path, adapter, if _instance: return _instance(row) - # determine identity key - identitykey = refresh_identity_key or ( - identity_class, - tuple([row[column] for column in pk_cols]) - ) - - instance = session_identity_map.get(identitykey) - - if instance is not None: - state = instance_state(instance) - dict_ = instance_dict(instance) - - isnew = state.runid != runid - currentload = not isnew - loaded_instance = False - - if version_check and not currentload and \ - version_id_col is not None and \ - mapper._get_state_attr_by_column( - state, - dict_, - mapper.version_id_col) != \ - row[version_id_col]: - - raise orm_exc.StaleDataError( - "Instance '%s' has version id '%s' which " - "does not match database-loaded version id '%s'." - % (state_str(state), - mapper._get_state_attr_by_column( - state, dict_, - mapper.version_id_col), - row[version_id_col])) - elif refresh_state: - # out of band refresh_state detected (i.e. its not in the - # session.identity_map) honor it anyway. this can happen - # if a _get() occurs within save_obj(), such as - # when eager_defaults is True. + # determine the state that we'll be populating + if refresh_identity_key: + # fixed state that we're refreshing state = refresh_state instance = state.obj() dict_ = instance_dict(instance) @@ -355,25 +324,65 @@ def instance_processor(mapper, context, result, path, adapter, currentload = True loaded_instance = False else: - # check for non-NULL values in the primary key columns, - # else no entity is returned for the row - if is_not_primary_key(identitykey[1]): - return None + # look at the row, see if that identity is in the + # session, or we have to create a new one + identitykey = ( + identity_class, + tuple([row[column] for column in pk_cols]) + ) - isnew = True - currentload = True - loaded_instance = True + instance = session_identity_map.get(identitykey) - instance = mapper.class_manager.new_instance() + if instance is not None: + # existing instance + state = instance_state(instance) + dict_ = instance_dict(instance) - dict_ = instance_dict(instance) - state = instance_state(instance) - state.key = identitykey + isnew = state.runid != runid + currentload = not isnew + loaded_instance = False + + if version_check and not currentload and \ + version_id_col is not None and \ + mapper._get_state_attr_by_column( + state, + dict_, + mapper.version_id_col) != \ + row[version_id_col]: + + raise orm_exc.StaleDataError( + "Instance '%s' has version id '%s' which " + "does not match database-loaded version id '%s'." + % (state_str(state), + mapper._get_state_attr_by_column( + state, dict_, + mapper.version_id_col), + row[version_id_col])) + else: + # create a new instance + + # check for non-NULL values in the primary key columns, + # else no entity is returned for the row + if is_not_primary_key(identitykey[1]): + return None + + isnew = True + currentload = True + loaded_instance = True + + instance = mapper.class_manager.new_instance() + + dict_ = instance_dict(instance) + state = instance_state(instance) + state.key = identitykey - # attach instance to session. - state.session_id = session_id - session_identity_map._add_unpresent(state, identitykey) + # attach instance to session. + state.session_id = session_id + session_identity_map._add_unpresent(state, identitykey) + # populate. this looks at whether this state is new + # for this load or was existing, and whether or not this + # row is the first row with this identity. if currentload or populate_existing: # full population routines. Objects here are either # just created, or we are doing a populate_existing |