docs: ADR-0044 relationship visualization (V1); accepted

Two-table connector diagrams (Style A) for relationships, resolving ADR-0016 OOS-1 and the open half of requirements.md V1. Reach is 'relationship-relevant' (show relationship / show table / relationship DDL echoes; incidental echoes keep prose). App-side rendering, width- adaptive side-by-side vs vertical, compound-FK pair routing, bold box title rows. Revised after a /runda DA pass corrected three inverted- architecture claims (App-side rendering, untracked output width, prose-in-worker show-relationship). Index updated per ADR-0000.
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 # ADR-0044: Relationship visualization (two-table connector diagrams)
 ## Status
 Accepted (2026-06-09)
 Resolves **ADR-0016 OOS-1** ("Relationship visualization — two
 structures side-by-side with an arrow; its own ADR; will compose
 `render_structure`"). Partially **supersedes ADR-0016 §5** (the
 plain-text `References:` / `Referenced by:` relationship block) and
 **extends ADR-0016 §4 and §6** (adds layout width-awareness and
 per-span styling). Builds on ADR-0028 (styled output runs),
 ADR-0043 (compound, list-based relationship endpoints), ADR-0013
 (named 1:n relationships), and the V5/V5a `show` family. Honours
 ADR-0009 (DSL conventions) and ADR-0002 (no engine name in
 user-facing strings).
 Closes the substantive open half of requirement **V1**
 (`docs/requirements.md`): "a selected relationship as two tables
 joined by a line."
 ## Context
 The table-structure half of V1 is done: `show table <T>` renders a
 box-drawn structure table (columns / types / constraints / indexes),
 and relationships appear **as prose** beneath it —
 `References:` / `Referenced by:` blocks formatted `A.col → B.col`
 (`output_render.rs render_structure`, per ADR-0016 §5). The same
 prose appears in V5a's `show relationship <name>` detail view.
 The open piece is the **visual** form: drawing a relationship as two
 tables side by side joined by a connecting line, with cardinality and
 referential actions. ADR-0016 deliberately deferred this (OOS-1) and
 **pre-sized the structure renderer to compose two of itself**. This
 ADR cashes that in.
 Three facts from the current architecture shape the design:
 1. **Rendering is App-side; the worker returns structured data.**
   *(Corrected from the initial draft after direct verification — an
   earlier survey had this backwards.)* The database worker (`db.rs`)
   returns `TableDescription` / `DataResult`; the **App** (`app.rs`)
   calls the `output_render.rs` helpers to format them into
   `OutputLine`s. Verified: every `render_structure` /
   `render_data_table` call site is in `app.rs` (557, 1669, 1732,
   1752, 1814, 1678, …); **none in `db.rs`**. Width and theme
   therefore live App-side. The **one exception** is the V5/V5a
   `show <kind> [<name>]` family: `do_show_one` / `show_list` build
   prose `Vec<String>` **in the worker** from `RelationshipSchema` /
   index metadata, carrying *no* `TableDescription` — so
   `show relationship <name>` is the path that must be restructured
   (§6). The output buffer is a flat `VecDeque<OutputLine>` — a
   historical log of lines, not re-renderable widgets (live
   re-rendering is V4 territory).
 2. **Relationships are list-based (ADR-0043).** `RelationshipSchema`
   /`RelationshipEnd` endpoints are `Vec<String>` column lists,
   positionally paired. Single-column FKs are the one-element case;
   the diagram must render compound FKs too.
 3. **Only 1:n relationships exist.** Relationships are declared 1:n
   (ADR-0013); m:n (requirement C4) is unbuilt, and there is no
   UNIQUE-target 1:1. So cardinality is always **1 on the parent
   (referenced) side, n on the child (referencing/FK) side**.
 The user has chosen the design direction across three decisions
 (recorded below as made): **visual style**, **where it appears**, and
 **multi-relationship layout**.
 ## Decision
 ### 1. Scope and trigger — diagrams where relationships are the subject
 Relationship diagrams replace the prose relationship form on the
 surfaces where **relationships are the subject of the command**; no
 new command or sigil is added (ADR-0009: one sigil, keyword grammar).
 This is the user-chosen **"relationship-relevant"** reach (over a
 global replacement of every structure echo, or a show-commands-only
 scope — see the DA pass).
 Diagram surfaces:
 - **`show relationship <name>`** (V5a) renders **one** diagram: the
  parent and child tables as **full structure boxes** joined by a
  connector. The canonical base unit.
 - **`show table <T>`** keeps T's full structure box at the top
  (unchanged from ADR-0016 §5), then a **Relationships** section:
  **one compact connector diagram per relationship**, stacked
  vertically (§4).
 - **Relationship DDL auto-shows** — the structure echo after
  `add 1:n relationship`, `drop relationship`, and a future
  `modify relationship` (C3a) — render their relationships as
  compact diagrams (§4), since the user just acted on a relationship.
 Prose-retained surfaces (**unchanged** from ADR-0016 §5):
 - **Incidental DDL auto-shows** — the structure echo after
  `create table`, `add`/`drop`/`rename`/`change column`,
  `add`/`drop index` — keep the terse `References:` /
  `Referenced by:` prose. A simple `add column` on a heavily-related
  table should not print a wall of diagrams.
 So this **partially supersedes ADR-0016 §5**: the prose block is
 replaced by diagrams on the relationship-subject surfaces and
 retained on incidental ones. No information is lost on either —
 relationship name, endpoints, cardinality, and `on delete` /
 `on update` actions all appear in both forms.
 Mechanically (§6) this is a **render mode** on `render_structure`
 (`Diagram` vs `Prose`), selected by the calling command; the items/
 side panel (`ui.rs render_items_panel`) is a navigation tree and is
 untouched.
 A future **user-configurable setting** (e.g. always-prose /
 always-diagram / auto-by-width, for small-screen users) is a clean
 follow-up and is **out of scope here** (OOS-7) — the per-command
 default above is the v1 behaviour.
 ### 2. The base diagram — Style A (structure + connector)
 A relationship diagram is two boxes plus a connector. Reading
 convention, applied **uniformly** (this is what makes
 multi-relationship lists scannable):
 - **Child (FK holder) on the left, parent (referenced) on the
  right.** The connector arrow always points **left → right**, in the
  direction of the reference (child *references* parent).
 - **Cardinality** sits at the connector ends: **`n`** at the child
  (left) end, **`1`** at the parent (right) end.
 - **Referential actions** (`on delete …`, `on update …`) label the
  connector beneath the line. `no action` is shown verbatim
  (ADR-0009 wording), abbreviated to the action keyword when space is
  tight.
 #### 2.1 Box anatomy — the table name must stand out
 Every box (full or compact) carries the table name as a **bold title
 row separated from the columns by a rule** (`├─┤`), styled in the
 table-name theme class (§5). This directly addresses the requirement
 that a name never read as just another column row.
 Full structure box (used in `show relationship`): title row, then the
 ADR-0016 column/type listing, with key markers (§2.2):
 ```
 ┌──────────────────────┐
 │ orders               │   ← bold title row (table name)
 ├──────────────┬───────┤
 │ id      (PK) │ int   │
 │ customer_id ●│ int   │   ● marks the FK column in this relationship
 │ total        │ real  │
 └──────────────┴───────┘
 ```
 Compact box (used in `show table`'s stacked list): title row, rule,
 then **only the column(s) participating in this relationship** — the
 focal table's full structure is already shown above, so the compact
 box stays small and the focal table is not redrawn in full N times:
 ```
 ┌──────────────┐
 │ orders       │   ← bold title row
 ├──────────────┤
 │ customer_id ●│   only the FK column(s) for this relationship
 └──────────────┘
 ```
 #### 2.2 Key markers
 - The PK is annotated `(PK)` (consistent with the existing structure
  view's constraint column).
 - The **endpoint columns of *this* relationship** are marked with a
  filled dot `●` adjacent to the column name — on the child FK
  column(s) and the parent referenced column(s). The connector
  attaches at these `●` rows.
 #### 2.3 The connector (single-column)
 `show relationship Customers_Orders` (child `orders.customer_id`
 → parent `customers.id`):
 ```
        orders                                customers
 ┌──────────────────────┐                  ┌─────────────────────┐
 │ orders               │                  │ customers           │
 ├──────────────┬───────┤            1 ┌──●│ id      (PK)        │
 │ id      (PK) │ int   │              │   ├─────────────┬───────┤
 │ customer_id ●│ int   │ n ───────────┘   │ name        │ text  │
 │ total        │ real  │                  │ email       │ text  │
 └──────────────┴───────┘                  └─────────────┴───────┘
 on delete cascade · on update no action
 ```
 **Connector routing.** The two `●` endpoint rows are generally at
 different heights. The connector leaves the child box's right edge at
 the child-`●` row, travels horizontally into a **gutter channel**
 between the boxes, jogs vertically to the parent-`●` row, then enters
 the parent box's left edge with an arrowhead. Box tops are aligned.
 (Exact glyphs/spacing are pinned by insta snapshots in
 implementation; the mockups here are representative, not normative.)
 #### 2.4 Compound foreign keys (ADR-0043)
 For an n-column FK, the n child `●` columns and n parent `●` columns
 are each listed, and **one connector is routed per positional pair**.
 A summary line states the pairing explicitly so it is unambiguous
 even if the routed lines are visually close:
 ```
              orders                              customers
 ┌──────────────────────────┐              ┌──────────────────────┐
 │ orders                   │          1 ┌●│ region   (PK)        │
 ├──────────────┬───────────┤            │ │ id       (PK)        │
 │ cust_region ●│ text      │ n ─────────┤ ├────────────┬─────────┤
 │ cust_id     ●│ int       │ n ─────────┘ │ name       │ text    │
 │ …            │ …         │              └────────────┴─────────┘
 └──────────────┴───────────┘
 (cust_region, cust_id) ──► customers.(region, id)
 on delete cascade · on update no action
 ```
 ### 3. Width handling and the narrow-terminal fallback
 The diagram is rendered **once, App-side, at the output-panel width
 current when the command runs**. The `App` does **not** track the
 panel width today — `note_output_viewport(visible_rows,
 total_wrapped_rows)` records only row counts for scroll math
 (verified; `App` has no width field). This ADR adds a
 `last_output_width: u16` to `App`, set from `ui.rs` where the output
 panel's `inner.width` is already computed (next to the existing
 `note_output_viewport` call), with an `80` default before the first
 render. The App-side render path then chooses layout per diagram:
 - **Side-by-side** (§2) when both boxes plus the gutter fit the
  available width.
 - **Vertical stack** when they do not: parent box above, child box
  below, connector running **downward** through a short vertical
  channel, cardinality and actions labelling it. This keeps a real
  diagram at any width instead of degrading to prose:
 ```
 ┌──────────────┐
 │ orders       │
 ├──────────────┤
 │ customer_id ●│ n
 └──────────────┘
        │  on delete cascade
        ▼  on update no action
 ┌──────────────┐
 │ customers    │
 ├──────────────┤
 │ id      (PK)●│ 1
 └──────────────┘
 ```
 - **Last-resort helper.** Only when even a single vertical diagram
  cannot fit (e.g. an extremely narrow pane, or a box wider than the
  pane), `show table` emits a one-line pointer per relationship —
  `<child> → <parent>  ·  run `show relationship <name>` for the
  diagram` — so nothing is silently dropped. `show relationship`
  itself always renders (it is the detail view); if its single box is
  wider than the pane, ratatui's existing right-edge handling applies
  (ADR-0016 §4), no new truncation.
 **No live reflow.** Because the output buffer is a historical line
 log, resizing the terminal *after* a diagram is rendered does not
 reflow it — identical to how every other rendered output behaves
 today. Reflow-on-resize belongs to V4's re-renderable journal and is
 explicitly out of scope (OOS-2).
 This **extends ADR-0016 §4**: that ADR added no width-awareness
 (relying on ratatui truncation); this ADR adds width-awareness for
 the **layout decision** only. It still performs **no per-cell
 truncation** (ADR-0016 OOS-4 stands).
 ### 4. `show table` multi-relationship layout — stacked compact diagrams
 After T's full structure box, a **Relationships** heading, then one
 **compact** diagram (§2.1) per relationship, stacked vertically.
 Ordering matches the current prose order: **outbound** (T is the
 child — "References") first, then **inbound** (T is the parent —
 "Referenced by"), each group ordered by relationship name. The
 child-left/parent-right rule (§2) is applied per diagram, so the
 focal table appears on the left for its outbound relationships and on
 the right for its inbound ones — consistent with the reference
 direction.
 ```
 orders
 ┌──────────────┬──────┐
 │ orders       │      │
 ├──────────────┼──────┤
 │ id      (PK) │ int  │
 │ customer_id  │ int  │
 │ total        │ real │
 └──────────────┴──────┘
 Relationships
 ┌──────────────┐  n          1  ┌─────────────┐
 │ orders       │────────────────│ customers   │
 ├──────────────┤  on delete     ├─────────────┤
 │ customer_id ●│  cascade       │ id   (PK)  ●│
 └──────────────┘                └─────────────┘
 ┌──────────────┐  n          1  ┌─────────────┐
 │ order_items  │────────────────│ orders      │
 ├──────────────┤  on delete     ├─────────────┤
 │ order_id    ●│  cascade       │ id   (PK)  ●│
 └──────────────┘                └─────────────┘
 ```
 Stacking (rather than a single focal-centred subgraph with fan-out
 connectors) is chosen because: it never produces crossing lines; it
 scales to any number of relationships via the pane's existing
 vertical scroll; each diagram is only two boxes wide, so it fits
 nearly any terminal; and it keeps the per-diagram width logic of §3
 trivial. The cost — the focal table name repeats per diagram — is
 mitigated by the compact box showing only the participating
 column(s).
 ### 5. Styling
 Styling uses the **ADR-0028 styled-run mechanism** (`OutputSpan` /
 `OutputStyleClass` on `OutputLine`), not raw text. New style classes
 (theme-defined, legible light/dark per ADR-0016 §6 / NFR-7):
 - **table name** — bold, accent colour (the "stand out" requirement);
 - **key marker** (`●`, `(PK)`) — a distinct accent;
 - **connector** (box-drawing line + arrowhead) — muted;
 - **cardinality** (`1` / `n`) — emphasised;
 - **referential action** label — muted/secondary.
 This **extends ADR-0016 §6** (which set up `OutputKind::System`
 styling but no per-element theming) by reusing the per-span
 `OutputSpan` path ADR-0028 later introduced — which is **already
 produced App-side** (`output_render.rs:299-332` builds styled runs
 for the explain-plan tree; `app.rs` constructs `OutputLine`s with
 `styled_runs: Some(..)`; `ui.rs:863` renders them). So **no
 worker→UI contract change is needed**: the new `output_render`
 diagram functions return styled lines directly on the App side
 (§6).
 ### 6. Implementation
 All rendering is **App-side** (per the corrected Context fact 1), in
 `output_render.rs` (hand-rolled, ADR-0016 §7), returning styled
 lines that `app.rs` pushes as `OutputLine`s with `styled_runs` set.
 No worker `available_width` and no worker→UI contract change.
 - **New renderer functions in `output_render.rs`**, composing the
  existing box primitives and emitting styled spans (§5):
  - `render_relationship_diagram(child, parent, rel, width, full) ->
    Vec<OutputLine>` — `full` selects full vs compact boxes;
    internally decides side-by-side vs vertical (§3) from `width`;
    routes the connector(s) including compound pairs (§2.4).
  - A shared helper for the box title row + key markers.
  - The two call paths supply `width` from the new
    `App::last_output_width` (§3).
 - **`show table <T>` (already App-side).** The focal
  `TableDescription` reaches `app.rs` and is rendered by
  `render_structure` today. `render_structure` is refactored to emit
  the focal structure box, then a **Relationships** section built
  from the focal description's `RelationshipEnd`s (which already
  carry neighbour table name + participating columns + cardinality +
  actions — **enough for the compact box**; no neighbour
  full-structure fetch needed). `render_structure` gains a
  **relationship render mode** (`Diagram` | `Prose`); the caller
  selects it (§1): `show table` and the relationship DDL echoes pass
  `Diagram`, incidental DDL echoes pass `Prose`. The generic
  `handle_dsl_success(command, description)` (`app.rs:1669`) already
  has the `Command`, so the mode is a function of the command
  variant; the incidental-only call sites (`app.rs:557/1732/1752/
  1814`) pass `Prose`.
 - **`show relationship <name>` (must be restructured).** Its
  worker path `do_show_one` currently returns prose `Vec<String>`
  from a `RelationshipSchema` only. To draw the **full** diagram the
  App needs **both** endpoint `TableDescription`s. The relationship
  detail reply is upgraded to carry the `RelationshipSchema` plus
  both endpoints' `TableDescription`s (the worker already has
  `do_describe_table`); the App renders the diagram. The
  "No relationship named `X`." not-found line is preserved.
 - **Self-referential FKs** (`parent_table == child_table`; supported
  in the grammar): render as two boxes bearing the same table name
  (child-left copy with the FK column, parent-right copy with the
  referenced column), connector as usual — clearer than a self-loop
  glyph in a TUI. Covered by a snapshot test.
 - **Out of these surfaces:** the items/side panel (`ui.rs:582`
  `render_items_panel`) is a navigation tree, not a relationship
  view, and is unchanged.
 - **Database engine name** never appears in any rendered string
  (ADR-0002).
 ### 7. Testing
 - **Insta snapshots** (Tier 2) pin exact rendered output for:
  single-column 1:n (`show relationship`); compound FK; the
  narrow-terminal vertical fallback; the last-resort helper line;
  a self-referential FK; and a `show table` with both an outbound and
  an inbound relationship (stacked compact list).
 - **Unit tests** (`output_render.rs`): the side-by-side-vs-vertical
  **width-threshold** decision at boundary widths; connector routing
  for endpoints at differing row heights; compound-pair routing;
  key-marker placement.
 - **Tier-3 integration**: `show relationship <name>` and
  `show table <T>` produce diagram output (not prose) end-to-end
  through the worker.
 - **Existing tests/code to update** (enumerated from a DA grep — the
  supersession of ADR-0016 §5 is not abstract):
  - `output_render.rs:121,135` — the `References:` / `Referenced by:`
    prose-emitting code in `render_structure`;
  - `output_render.rs:78` — the docstring deferral note (OOS-1);
  - `output_render.rs:793` — unit test asserting `"Referenced by:"`;
  - `src/snapshots/…render_structure_with_relationships.snap` — the
    prose snapshot;
  - `tests/it/walking_skeleton.rs:477,530` — integration asserts on
    `"Referenced by:"` (and the comment at 433);
  - `src/dsl/command.rs:984` — a comment referencing the prose (no
    behaviour).
  If the scope fork resolves to "all `render_structure` call sites,"
  the DDL-echo snapshots for create-table / add-column / drop-index /
  change-column auto-shows also churn — to be re-recorded with
  `cargo insta`. No test is deleted to hide a regression; each change
  is a deliberate format update.
 ### 8. Out of scope
 - **OOS-1.** Live reflow-on-resize of already-rendered diagrams —
  V4's re-renderable journal (requirement V4).
 - **OOS-2.** Whole-database ER diagram / export (requirement V3).
 - **OOS-3.** m:n relationships (requirement C4, unbuilt). Only the
  existing 1:n form is rendered.
 - **OOS-4.** ASCII fallback for terminals without box-drawing
  (inherits ADR-0016 OOS-5).
 - **OOS-5.** Per-cell colouring of column *data* values (ADR-0016
  OOS-3 / NFR-5) — unrelated to relationship structure.
 - **OOS-6.** Cell-level truncation with ellipsis (ADR-0016 OOS-4
  stands).
 - **OOS-7.** A user-configurable relationship-display setting
  (always-prose / always-diagram / auto-by-width — useful for small
  screens). The §1 per-command default is v1; the setting is a clean
  later follow-up (user-flagged 2026-06-09).
 ## Consequences
 - Requirement **V1** is fully satisfied: relationships render as
  two-table connector diagrams in both `show relationship <name>`
  (full) and `show table <T>` (stacked compact), superseding the
  prose form.
 - `output_render.rs` grows a relationship renderer that **composes**
  the box primitives exactly as ADR-0016 anticipated; the worker→UI
  show contract becomes styled-line-based, a small generalisation
  reusable by other styled `show` output later.
 - The worker gains an `available_width` input for `show` — the first
  width-aware formatting in the codebase. The decision is a snapshot
  at command time; no resize machinery is introduced.
 - Compound FKs (ADR-0043) get their first dedicated visualization,
  with explicit positional-pair labelling.
 - The historical-log output model is preserved (no widget/reflow
  model); V4 remains the home for a re-renderable journal.
 - Box-drawing is required (no ASCII fallback), consistent with
  ADR-0016.
 ## Devil's Advocate / runda pass (2026-06-09)
 A planning-time DA pass (empirical, against the code) corrected three
 foundational errors carried in from an initial code survey, and
 surfaced one open fork:
 1. **Rendering boundary was inverted** (fixed in Context 1 / §6):
   `render_structure` / `render_data_table` run **App-side**
   (`app.rs`), not in the worker. Rendering, width, and theme are all
   App-side — simpler than the draft assumed.
 2. **Width was claimed "already tracked"; it is not** (fixed in §3):
   `note_output_viewport` records only rows. A new
   `App::last_output_width` (set from `ui.rs`) is required.
 3. **`show relationship <name>` renders prose in the worker** (fixed
   in §6): `do_show_one` carries only a `RelationshipSchema`. The
   detail reply must be upgraded to include both endpoint
   `TableDescription`s for the full diagram.
 4. **Styled-line contract was over-stated** (fixed in §5): styled
   runs are already produced App-side (explain plan); no worker→UI
   contract change.
 **Resolved fork (user, 2026-06-09): "relationship-relevant" reach.**
 Diagrams render on the surfaces where the relationship is the subject
 (`show table`, `show relationship`, relationship DDL echoes);
 incidental DDL echoes keep prose (§1) — avoiding a wall of diagrams
 after an `add column`. A future user-configurable display setting is
 noted as OOS-7. This also records V1's **deliberate scope expansion**
 beyond its literal "a selected relationship" wording into
 multi-relationship surfaces, to be reflected in `requirements.md`.
 All design forks are now resolved and the architecture is corrected.
 The user accepted this revised ADR on 2026-06-09; status is
 **Accepted** and implementation proceeds test-first.
@@ -49,3 +49,4 @@ This directory contains the project's ADRs, recorded per
 - [ADR-0041 — Copy the output panel to the system clipboard](0041-copy-output-to-clipboard.md) — **Accepted 2026-06-02 (issue #11)**, amends ADR-0003's app-command registry (adds **`copy`** / `copy all` / `copy last`). The friction it removes: filing a bug report meant terminal-selecting the output panel and fighting wrapping/borders. New **app-level command** (sigil-free, both modes): `copy` / `copy all` copy the whole panel; `copy last` copies from the most recent echo line to the end. **Mechanism — OSC 52 *and* native (`arboard`), always both**, because OSC 52 acceptance is undetectable (no terminal ack), so a true "fall back when unsupported" can't be built: emit the OSC 52 escape (no new dep — `base64`+`crossterm`; works over SSH; tmux-passthrough-wrapped via `$TMUX`), then a best-effort native write whose failure is ignored (headless host — OSC 52 carried it); the two carry identical content. **Format — plain text verbatim as rendered** (tags, `✓`/`✗`, box-drawing) joined by `\n`, without viewport padding/wrapping; a drift-lock test pins `OutputLine::plain_text` to `render_output_line`. `arboard` added **`--no-default-features`** (drops the `image` crate; X11-only on Linux — `wayland-data-control` deliberately omitted as it ~doubles the dep tree and OSC 52 covers native-Wayland). Security: write-only, scans clean for arboard's tree (cargo audit / osv-scanner / grype), 1Password-maintained, minimal surface. OOS: Markdown export, selection/range, a keybinding, OSC 52 read, `screen` passthrough
 - [ADR-0042 — H1a parse-error pedagogy in the grammar-tree era](0042-h1a-parse-error-pedagogy-grammar-tree.md) — **Accepted 2026-06-03.** Continues **H1a** from ADR-0021 against the ADR-0024 grammar tree (ADR-0021's chumsky mechanism is dead). Records the **baseline already shipped** — per-command `usage:` block (38 `parse.usage.*` templates), available-commands fallback, structural "after `…`, expected …" wording, source-derived ident slot labels ("table name"/"column name"), curated `parse.custom.*` near-miss messages, and the ADR-0027/0033/0036 schema-aware `[ERR]` diagnostics — so H1a is *substantially* delivered at the intent level. Defines the remaining work as **(1)** a verified per-command **near-miss matrix** (`tests/typing_surface/` + `tests/it/parse_error_pedagogy.rs`) as the definition of done, test-first; **(2)** **friendlier literal expectation labels** — optional prose glosses on `Word`/`Punct`/`Flag` positions that *add* role context while always keeping the exact literal visible (e.g. "a filter clause: `where …` or `--all-rows`"); **(3)** **advanced-mode SQL** near-miss parity (RETURNING scope, CTE-arity positioning, `CROSS JOIN … ON`, INSERT…SELECT count) — **in scope**, kept distinct from ADR-0019 §OOS-2 which covers advanced-SQL *engine*-error sanitisation, a different layer. Catalog/anchor-phrase discipline (ADR-0019) preserved; no public API change. OOS: I3/I4, spell-correction, multi-error reporting, verbosity-gating the usage block
 - [ADR-0043 — Compound-primary-key foreign-key references (T3)](0043-compound-pk-foreign-key-references.md) — **Accepted + implemented 2026-06-09** (all four forks confirmed at the recommended option: full-PK matching, house-style uniform lists, parenthesized DSL syntax, bare-SQL-FK auto-expansion). Closes `requirements.md` **T3** `[x]` — the relationship model went list-based across six layers (single-column preserved, no migration), DSL `from P.(a,b) to C.(x,y)` + SQL `FOREIGN KEY (a,b) REFERENCES P(x,y)` parse/execute/enforce, 12 tests in `tests/it/compound_fk.rs`. Closes the open leg of `requirements.md` **T3**: a foreign key that *references* a parent's compound primary key. A 2026-06-09 audit found single-column FK woven through ~15–20 sites (metadata table, `RelationshipSchema`, `project.yaml` `RawEndpoint`, both grammar surfaces, executor FK-DDL emission, per-column type-compat, display) — earns an ADR, not an inline build. **Decision:** reference the parent's **full** compound PK, matched **positionally** to an equal-length child column list, per-pair `fk_target_type` compat (ADR-0011, element-wise); DSL `from <P>.(a, b) to <C>.(x, y)` (single form unchanged), SQL `FOREIGN KEY (x, y) REFERENCES P(a, b)` (extend the existing one-cap lists; bare table-level FK auto-expands to the parent PK when arities match). **Storage — no migration (back-compat not required, user-confirmed 2026-06-09; no installed base):** the relationship endpoint joins the list convention `project.yaml` *already* uses — `columns: [a, b]` like `primary_key: [id]` and index `columns: [...]` (the endpoint was the lone scalar `column:` holdout); the metadata `TEXT` columns are unchanged and store the list **comma-joined** (`a,b`; the bare name for single — safe because identifiers are `[A-Za-z0-9_]+`). No F3 migrator, no version bump; accepted trade-off is that a pre-change `project.yaml` with relationships won't load (clean cutover). In-memory model goes list-based (`Vec<String>`) through all six layers; the enforced FK is the rebuilt child-table DDL (`FOREIGN KEY (a,b) REFERENCES P(x,y)`), one relationship = one undo step (ADR-0013). Genuine forks escalated: matching policy (full-PK vs subset), storage (house-style uniform lists vs normalized table), DSL syntax (parenthesized vs repeated-dotted), bare-SQL-FK auto-expansion. OOS: subset/non-PK (UNIQUE-targeted) FK references; any single-column behaviour change
 - [ADR-0044 — Relationship visualization (two-table connector diagrams)](0044-relationship-visualization.md) — **Accepted 2026-06-09** (revised post-`/runda` DA pass). Resolves **ADR-0016 OOS-1** and closes the open half of `requirements.md` **V1** ("a selected relationship as two tables joined by a line"). Renders a relationship as **Style A** (two structure boxes + connector). **Reach = "relationship-relevant"** (user-chosen over global / show-only): diagrams on the surfaces where the relationship is the *subject* — `show relationship <name>` (one full diagram), `show table <T>` (T's structure box then a **Relationships** section of **stacked compact** per-relationship diagrams — chosen over a focal-centred subgraph: no crossing lines, scales via scroll, two-boxes-wide fits any terminal), and relationship DDL echoes (`add`/`drop`/`modify relationship`); incidental DDL echoes (`add column`, `drop index`, `change column`, plain `create table`) keep the terse prose, via a `Diagram`|`Prose` render mode on `render_structure`. Reading convention **child(FK)-left / parent-right, arrow →, `n`…`1` cardinality**, applied uniformly; every box gets a **bold title row + rule** so the name can't read as a column. **Compound FKs** (ADR-0043) route one connector per positional pair + an explicit pairing line. **Width-aware** (first in the codebase) but **App-side**: `render_structure`/diagram rendering runs in `app.rs` (the worker only returns `TableDescription`s), a new `App::last_output_width` (set from `ui.rs`) drives side-by-side vs a **vertical-stack** fallback + last-resort "run `show relationship`" pointer; rendered once at command time, **no live reflow** (V4). `show relationship`'s worker path (`do_show_one`, prose-only) is restructured to return both endpoint `TableDescription`s. Styling reuses **ADR-0028** App-side styled runs (new classes: table-name/key/connector/cardinality/action) — no worker→UI contract change. **Partially supersedes ADR-0016 §5** (prose block replaced on relationship-subject surfaces, retained on incidental ones); extends §4 (layout width-awareness, still no cell truncation) and §6 (per-span theming). Tests: insta snapshots (single, compound, vertical fallback, helper line, self-referential, multi-rel `show table`) + width-threshold/routing unit tests + Tier-3 wiring; enumerated prose-fallout updates (`output_render.rs:121/135/793`, the relationships snapshot, `walking_skeleton.rs:477/530`). A `/runda` DA pass corrected three inverted-architecture claims (App-side rendering, untracked width, prose-in-worker show-relationship) before acceptance. OOS: user-configurable display setting (OOS-7), live reflow (V4), whole-DB ER export (V3), m:n (C4), ASCII fallback (ADR-0016 OOS-5)