- `backlink C.f` field type: parsed, typed as `multi C`, and VIRTUAL —
filtered out of the stored row layout (no column, omittable in
ctor/insert), collected in clsrec.cr_backlinks
- reading a backlink (`d.staff`) lowers to DB_PROBE on the source
class's index for the backing column (backlink_target resolves the
(source class, index number); a backlink with no backing index has
no efficient read)
- `ref C` navigation (`e.dept.name`) chains: a ref value is the target
row's id, so a `Ref C` base navigates into C's fields exactly like a
table-class value, routing to DB_GET_FIELD both in typecheck and emit
- query navigation source `from s in d.staff`: emit_query evaluates the
nav expr to get its id-list instead of DB_SCAN; QNav typechecks with
the range var bound to the navigation's element class
- fixture run/db-query-relations proves both directions; oop-e2e 75/0,
woc-test 566/0, log-watcher 7/0
- still ahead for employee: order/take, group-by aggregates, projection
records, delete + update-through-row
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>