claude@clouddev1
a50c6cdf70
Adds tests/typing_surface/where_expression.rs — 9 matrix cells for the complex WHERE / show-data limit typing surface: operator candidates after an operand, AND / OR after a predicate, NOT, BETWEEN / IN bounds, and `show data` where / limit. Writing the cells surfaced a grammar bug. `predicate_tail`'s `[NOT] negatable` branch started with `Optional(not)`, and an Optional-first `Seq` always "commits" — so on an incomplete input the walker's `Choice` returned that branch's `Incomplete` early and discarded every sibling branch's expected set, dropping `is` and the comparison operators from completion after a column. Fixed by splitting it into explicit `NOT negatable` and bare `negatable` branches — no `predicate_tail` branch starts with an `Optional` now. The matched terminal sequence is unchanged, so `build_expr` is untouched. Docs: ADR-0026 gains an "As-built notes" section recording the option-1 builder realization, its two deviations from the §3 sketch, and the deferral of §7 diagnostic flagging to ADR-0027. requirements.md C5a -> [x] (steps 1-4) with the test baseline refreshed to 1079; CLAUDE.md's deferred list reconciled (C5a implemented; the QA1/QA2 note now points at ADR-0028).
233 lines
11 KiB
Markdown
233 lines
11 KiB
Markdown
# RDBMS Playground — project notes for Claude
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## What this project is
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A cross-platform TUI application that gives learners a sandbox for
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exploring relational database concepts: tables, columns, primary
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and foreign keys, relationships, indexes, queries, and query
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plans. The audience is students from beginners to those ready for
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raw SQL, and the design accommodates both ends of that spectrum.
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The application is a teaching tool, not a database administration
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tool. Decisions about the type system, command surface, and
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backend choices are skewed toward pedagogy over breadth.
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## Authoritative decisions
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All significant design decisions live in `docs/adr/`. Read
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`docs/adr/README.md` for the index. **Before proposing changes
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that touch a decided area, read the relevant ADR.** Decisions are
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not re-litigated casually — if a decision needs to change, write a
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new ADR that supersedes the old one.
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Current decisions at a glance (each backed by an ADR):
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- **Stack:** Rust + Ratatui + Crossterm; `sqlparser-rs` reserved
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for SQL (advanced mode, not yet wired); `chumsky` for the DSL;
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`rusqlite` for the database (ADR-0001).
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- **Backend:** SQLite with `STRICT` tables and FK enforcement on
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(ADR-0002). Database access through a dedicated worker thread
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with mpsc/oneshot request channels (ADR-0010).
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- **Input:** simple mode (DSL only) by default; advanced mode
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(SQL + app-level commands) on toggle; `:` one-shot escape from
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simple to advanced (ADR-0003). No other sigils.
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- **Project format:** `project.yaml` + `data/<table>.csv` +
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`history.log`; `playground.db` is a derived artifact (ADR-0004,
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amended by ADR-0015). Implemented through Iteration 4 +
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cleanup; export/import (Iter 5) and migration framework /
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--resume / persistent input history (Iter 6) pending.
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- **Project storage runtime:** every command persists through to
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db + yaml + csv + history.log in one execution context, gated
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by the combined db persistence logic; commit-db-last ordering
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for crash-recoverable state; existence-only load + explicit
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`rebuild` command; in-TUI list-with-browse load picker; lock
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file for single-instance enforcement; persistence failures
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are fatal (banner + quit) (ADR-0015). Empty tables produce no
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CSV. CSV reader hand-rolled to preserve NULL-vs-empty
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distinction. Temp projects are marked by a literal `[temp]`
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segment in their directory name (validate_user_name rejects
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brackets, so user-named projects can never collide).
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- **Temp project cleanup:** unmodified empty temps
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(kind=Temp, empty schema, empty data dir) are auto-deleted
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on switch and on quit by `safely_delete_temp_project`,
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which stacks containment / symlink-rejection /
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`[temp]`-marker / contents-allowlist guards. Anything
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unexpected → refuse, never delete the wrong thing.
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- **Types:** `text`, `int`, `real`, `decimal`, `bool`, `date`,
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`datetime`, `blob`, `serial`, `shortid`. Compound primary keys
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supported. No real UUIDs (ADR-0005). FK column type
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compatibility via `Type::fk_target_type()` — `serial → int`,
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`shortid → text`, others identity (ADR-0011).
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- **Safety:** auto-snapshot before destructive ops; `:undo`;
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append-only `history.log` for replay and scripting (ADR-0006).
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*(Designed; not yet implemented.)*
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- **Sharing:** `export` command produces a zip without the `.db`;
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no hosted publishing (ADR-0007).
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- **Testing:** four-tier strategy from `cargo test` units up to
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PTY-based end-to-end (ADR-0008). Tiers 1–3 are active; Tier 4
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is wired only for the listed critical flows.
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- **DSL syntax conventions:** required clauses use keyword
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grammar (`with pk`, `to table` optional, `from..to`, `set`,
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`where`); `--` flags are reserved for opt-in choices; one
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sigil only (`:`); keywords case-insensitive, identifiers
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case-preserving (ADR-0009).
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- **Internal metadata tables** (ADR-0012, ADR-0013): the database
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carries `__rdbms_playground_columns` for user-facing column
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types and `__rdbms_playground_relationships` for named FKs.
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These are the source of truth for round-tripping schema info.
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Internal tables follow the `__rdbms_*` naming convention and
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are filtered out of `list_tables`.
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- **FK relationships:** declared via `add 1:n relationship [as
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<name>] from <P>.<col> to <C>.<col> [on delete <action>] [on
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update <action>] [--create-fk]`. Implemented through the
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rebuild-table primitive — the same machinery covers B2's
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pending column drop/rename/type-change use cases (ADR-0013).
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- **Data operations:** `insert / update / delete / show data`
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with required WHERE plus `--all-rows` opt-in for unfiltered
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ops; auto-show after writes shows just the affected rows;
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DELETE reports per-relationship cascade summaries (ADR-0014).
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## Repository layout
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```
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.
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├── Cargo.toml # dependencies, lints (nursery)
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├── CLAUDE.md # this file
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├── docs/
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│ ├── adr/ # all decision records (read 0000 first)
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│ ├── handoff/ # session-handover notes
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│ └── requirements.md # the Phase-1 checklist with progress
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├── src/
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│ ├── action.rs # Action enum (Quit / ExecuteDsl)
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│ ├── app.rs # App state + pure update() + Tier-1 tests
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│ ├── cli.rs # CLI args (--theme, --log-file)
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│ ├── db.rs # rusqlite worker, all DDL/DML, metadata tables
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│ ├── dsl/
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│ │ ├── action.rs # ReferentialAction enum + parsing
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│ │ ├── command.rs # Command AST + RelationshipSelector + RowFilter
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│ │ ├── mod.rs # re-exports
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│ │ ├── parser.rs # chumsky grammar (all DSL commands)
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│ │ ├── shortid.rs # base58 generator + validator
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│ │ ├── types.rs # user-facing Type enum + fk_target_type
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│ │ └── value.rs # Value/Bound + per-type validation
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│ ├── event.rs # AppEvent (input + DSL outcomes)
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│ ├── lib.rs # module re-exports for tests
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│ ├── logging.rs # tracing setup, file-backed
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│ ├── main.rs # binary entry; thin
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│ ├── mode.rs # Simple/Advanced mode enum
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│ ├── runtime.rs # Tokio loop, terminal setup, dispatch
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│ ├── snapshots/ # insta snapshots for Tier-2 tests
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│ ├── theme.rs # light/dark themes
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│ └── ui.rs # ratatui rendering
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└── tests/
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└── walking_skeleton.rs # Tier-3 integration tests
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```
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Key invariants in the code:
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- **`update()` is pure-sync.** It returns `Vec<Action>` for the
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runtime to enact. Side effects belong in the runtime, not the
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update function — that's what makes Tier 1/3 tests tractable.
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- **Database access goes through the worker thread.** Always.
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No direct `rusqlite::Connection` use outside `db.rs`.
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- **Schema mutations update metadata in the same transaction.**
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See ADR-0012 / ADR-0013. Adding a new DDL operation must keep
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the column- and relationship-metadata tables in sync.
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- **Renderer is pure render of `App` state.** It reports
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viewport metrics back via `note_output_viewport` so subsequent
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scroll input is wrap-aware.
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## Working style for this project
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- **Documentation discipline.** Significant decisions get an
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ADR. In-flight discussion stays in conversation or issues
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until it settles. The ADR-0000 index-upkeep rule applies:
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every ADR change updates `docs/adr/README.md` in the same
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edit.
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- **Testing.** Per the user's global standards, tests are
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established before changes, bugs are reproduced with failing
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tests before being fixed, and "all green, no skips" is the
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only acceptable end state. Integration tests exercise full
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flows.
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- **No silent feature loss.** Anything in an ADR is decided. If
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implementation reveals that a decision is wrong or
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impractical, raise it explicitly and update the ADR — do not
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quietly drift.
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- **Pedagogy wins ties.** When a design choice trades clarity
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for raw capability, prefer clarity. Real RDBMS power-user
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features exist; this app is not the place to teach them.
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- **No engine name in user-facing strings.** The choice of
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database engine is an implementation detail per ADR-0002
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(User-facing posture). Error messages, success notes,
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help text, and any other user-visible string refer to
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"the database" or "the engine" in the abstract — never
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the specific product (SQLite, STRICT, rusqlite, PRAGMA).
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ADR-internal prose and code comments may name it where
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technically necessary for precision.
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- **Confirm commits.** Per the user's global rules, every
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`git commit` is preceded by an explicit message proposal
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and user approval. No AI attribution in commit messages.
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## Things deliberately deferred
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These are explicitly tracked (mostly in `requirements.md`) but
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not yet implemented:
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- **Project storage** (track 2): largely implemented through
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Iteration 4 + cleanup pass + safety hardening (Iterations
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1–4 of ADR-0015). Pending pieces: `export` / `import` (Iter
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5), `--resume` + persistent input history hydration +
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migration framework scaffold (Iter 6).
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- **Complex WHERE expressions** (C5a): implemented through
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ADR-0026 steps 1–4 — the stratified expression grammar
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(AND/OR/NOT, the six comparisons, LIKE/IN/BETWEEN/IS NULL,
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parentheses) reached through a new `Subgrammar` node, the
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recursive `Expr` AST + parameterised SQL, and `where` /
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`limit` on `show data`. Type-mismatched comparisons run
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permissively (§7). Still pending: the §7 advisory
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*flagging* of type mismatches / `= NULL`, the seam with
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ADR-0027's diagnostics-severity model.
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- **SQL handling in advanced mode** (Q1): `sqlparser-rs` parser
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+ a defined SQL subset (Q4 — its own ADR).
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- **Column drops/renames/type changes** (B2 / C2 partial): the
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rebuild-table primitive (ADR-0013) is in place; the grammar
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and dispatch are pending.
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- **Indexes**: `add index` / `drop index` done (ADR-0025).
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`EXPLAIN QUERY PLAN` (QA1 / QA2) is designed in ADR-0028 —
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the `explain` prefix command + span-styled plan tree —
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but not yet implemented.
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- **Modify relationship** (C3a): drop+add covers the use case
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today.
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- **m:n convenience** (C4): auto-generates a junction table
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with appropriate FKs — depends on relationships being solid
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(they are).
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- **Friendly error layer** (H1): partial — FK errors are
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enriched both ways; full SQL→English translation pending.
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- **Strong syntax-help in parse errors** (H1a): point users at
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missing keywords/clauses rather than the unexpected
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character.
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- **Snapshot/replay/undo** (U-series): designed in ADR-0006;
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not yet implemented.
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- **Tutorial/lesson system**: acknowledged as in scope for
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design; needs its own ADR.
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- **Session log + Markdown export** (V4): the bigger UX
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project — scrollable session journal, smart structure
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rendering, save-as-markdown.
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- **Readline shortcuts** (I1b): Ctrl-A/Ctrl-E, Ctrl-W/Ctrl-K/
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Ctrl-U.
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- **Multi-line input** (I1): Enter inserts newline,
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Ctrl-Enter submits.
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- **Tab completion** (I3), **syntax highlighting** (I4).
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- **ER diagram export** (V3).
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- **CI** (TT5): test infrastructure exists; CI workflow not
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yet configured.
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## Handoff notes
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When taking over a session, read in order:
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1. `docs/handoff/` — most recent file gives session context.
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2. `CLAUDE.md` (this file).
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3. `docs/requirements.md` — current progress on each item.
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4. `docs/adr/README.md` and any ADR you'll touch.
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