Add foreign keys to advanced-mode SQL CREATE TABLE — the SQL spelling of
an ADR-0013 named relationship, created in the same transaction as the
table (one undo step).
- Grammar: inline `<col> … REFERENCES <parent>[(<col>)] [ON DELETE/UPDATE
…]` (a new column constraint) and table-level `[CONSTRAINT <name>]
FOREIGN KEY (<col>) REFERENCES …` (two new element branches — both
start on a concrete keyword, never a leading Optional, which would
abort the element Choice). Referential clauses reuse
shared::REFERENTIAL_CLAUSES.
- Builder: greedy FK-clause consumption (parens consumed internally so
they don't perturb the 4a.3 element-boundary depth tracker); inline FK
auto-named, table FK takes an optional CONSTRAINT name.
- Worker: do_create_table resolves + validates each FK before building
the DDL (self-ref validates against the in-statement columns/PK; bare
REFERENCES resolves to the parent's single-column PK, composite ->
error; PK-target + Type::fk_target_type compatibility), emits the
FOREIGN KEY clause identically to schema_to_ddl, and writes the
relationship metadata in the create transaction.
- Reuse: name/uniqueness/metadata-insert/type-compat factored into shared
helpers; do_add_relationship refactored to use them.
- FKs round-trip via the existing relationship plumbing (no new
persistence structures); describe surfaces the relationship.
Self-references and bare `REFERENCES <parent>` supported (user-confirmed).
Self-ref pre-submit indicator wrinkle deferred to 4i (tracked in ADR §13,
a code comment, and the plan).
DA/runda round added cross-cutting probes (FK survives the add-column
rebuild + a later rebuild_from_text; referential actions survive rebuild;
drop-child clears the relationship; drop-parent refused; bare self-ref
resolves to own PK) — all green, no fixes needed.
27 new tests (grammar/builder + Tier-3). Docs: ADR-0035 Status/§13,
README, requirements.md Q1.
Tests: 1795 passing, 0 failing, 1 ignored. Clippy clean.