initiate a column-based attribute refresh operation.
(mapper, state, attribute_names, passive)
| 1599 | |
| 1600 | |
| 1601 | def load_scalar_attributes(mapper, state, attribute_names, passive): |
| 1602 | """initiate a column-based attribute refresh operation.""" |
| 1603 | |
| 1604 | # assert mapper is _state_mapper(state) |
| 1605 | session = state.session |
| 1606 | if not session: |
| 1607 | raise orm_exc.DetachedInstanceError( |
| 1608 | "Instance %s is not bound to a Session; " |
| 1609 | "attribute refresh operation cannot proceed" % (state_str(state)) |
| 1610 | ) |
| 1611 | |
| 1612 | no_autoflush = bool(passive & attributes.NO_AUTOFLUSH) |
| 1613 | |
| 1614 | # in the case of inheritance, particularly concrete and abstract |
| 1615 | # concrete inheritance, the class manager might have some keys |
| 1616 | # of attributes on the superclass that we didn't actually map. |
| 1617 | # These could be mapped as "concrete, don't load" or could be completely |
| 1618 | # excluded from the mapping and we know nothing about them. Filter them |
| 1619 | # here to prevent them from coming through. |
| 1620 | if attribute_names: |
| 1621 | attribute_names = attribute_names.intersection(mapper.attrs.keys()) |
| 1622 | |
| 1623 | if mapper.inherits and not mapper.concrete: |
| 1624 | # load based on committed attributes in the object, formed into |
| 1625 | # a truncated SELECT that only includes relevant tables. does not |
| 1626 | # currently use state.key |
| 1627 | statement = mapper._optimized_get_statement(state, attribute_names) |
| 1628 | if statement is not None: |
| 1629 | # undefer() isn't needed here because statement has the |
| 1630 | # columns needed already, this implicitly undefers that column |
| 1631 | stmt = FromStatement(mapper, statement) |
| 1632 | |
| 1633 | return load_on_ident( |
| 1634 | session, |
| 1635 | stmt, |
| 1636 | None, |
| 1637 | only_load_props=attribute_names, |
| 1638 | refresh_state=state, |
| 1639 | no_autoflush=no_autoflush, |
| 1640 | ) |
| 1641 | |
| 1642 | # normal load, use state.key as the identity to SELECT |
| 1643 | has_key = bool(state.key) |
| 1644 | |
| 1645 | if has_key: |
| 1646 | identity_key = state.key |
| 1647 | else: |
| 1648 | # this codepath is rare - only valid when inside a flush, and the |
| 1649 | # object is becoming persistent but hasn't yet been assigned |
| 1650 | # an identity_key. |
| 1651 | # check here to ensure we have the attrs we need. |
| 1652 | pk_attrs = [ |
| 1653 | mapper._columntoproperty[col].key for col in mapper.primary_key |
| 1654 | ] |
| 1655 | if state.expired_attributes.intersection(pk_attrs): |
| 1656 | raise sa_exc.InvalidRequestError( |
| 1657 | "Instance %s cannot be refreshed - it's not " |
| 1658 | " persistent and does not " |
nothing calls this directly
no test coverage detected