# Architecture Decision Records

This directory contains the project's ADRs, recorded per
[ADR-0000](0000-record-architecture-decisions.md).

## Index

- [ADR-0000 — Record architecture decisions](0000-record-architecture-decisions.md)
- [ADR-0001 — Language and TUI framework](0001-language-and-tui-framework.md)
- [ADR-0002 — Database engine](0002-database-engine.md)
- [ADR-0003 — Input modes and command dispatch](0003-input-modes-and-command-dispatch.md)
- [ADR-0004 — Project file format](0004-project-file-format.md)
- [ADR-0005 — Column type vocabulary](0005-column-type-vocabulary.md)
- [ADR-0006 — Undo snapshots and replay log](0006-undo-snapshots-and-replay-log.md)
- [ADR-0007 — Sharing and export](0007-sharing-and-export.md)
- [ADR-0008 — Testing approach](0008-testing-approach.md)
- [ADR-0009 — DSL command syntax conventions](0009-dsl-command-syntax-conventions.md)
- [ADR-0010 — Database access via a dedicated worker thread](0010-database-access-via-worker-thread.md)
- [ADR-0011 — Foreign-key column type compatibility](0011-fk-column-type-compatibility.md)
- [ADR-0012 — Internal metadata for user-facing column types](0012-internal-metadata-for-user-facing-types.md)
- [ADR-0013 — Relationships, naming, and the rebuild-table strategy](0013-relationships-and-rebuild-table.md)
- [ADR-0014 — Data operations, value literals, and the auto-show pattern](0014-data-operations-and-value-model.md)
- [ADR-0015 — Project storage runtime](0015-project-storage-runtime.md)
- [ADR-0016 — Pretty table rendering for data and structure views](0016-pretty-table-rendering.md)
- [ADR-0017 — Column type-change compatibility](0017-column-type-change-compatibility.md)
- [ADR-0018 — Auto-fill contracts for `serial` and `shortid` columns](0018-auto-fill-contracts-for-serial-and-shortid.md)
- [ADR-0019 — Friendly error layer (H1) and i18n message catalog](0019-friendly-error-layer-and-i18n.md)
- [ADR-0020 — Tokenization layer for the DSL parser](0020-tokenization-layer-for-the-dsl-parser.md)
- [ADR-0021 — Parser-as-source-of-truth for H1a (per-command usage in parse errors)](0021-parser-as-source-of-truth-for-h1a.md)
- [ADR-0022 — Ambient typing assistance: colour, hint panel, completion (I3 + I4)](0022-ambient-typing-assistance.md)
- [ADR-0023 — Unified declarative grammar tree](0023-unified-grammar-tree.md) — direction (superseded for execution detail by ADR-0024)
- [ADR-0024 — Unified grammar tree: execution plan](0024-unified-grammar-tree-execution-plan.md) — **Accepted**, the executable spec — implemented (Phases A–F; Phase F shipped "minimal", `parser.rs` retained as the router — see the ADR's Phase F implementation note)
- [ADR-0025 — Indexes](0025-indexes.md) — **Accepted**, `add index` / `drop index`, persistence, rebuild-table preservation, and items-list display (`C3` index portion + `S2`)
- [ADR-0026 — Complex WHERE expressions](0026-complex-where-expressions.md) — **Accepted**, stratified recursive expression grammar (`AND`/`OR`/`NOT`, comparisons, `LIKE`, `IS NULL`, `IN`, `BETWEEN`) for `update` / `delete` / `show data` filters; `show data` gains `where` + `limit`; adds the `Subgrammar` node and a recursive `Expr` AST (`C5a`)
- [ADR-0027 — Input-field validity indicator](0027-input-validity-indicator.md) — **Accepted**, a debounced `[ERR]` / `[WRN]` marker at the input row's right edge, backed by a walker diagnostics-severity model (parse-outcome + schema-existence); advisory, never blocks submission (`S6`); Amendment 1 adds a `LIKE`-on-numeric-column WARNING
- [ADR-0028 — Query plans (`EXPLAIN QUERY PLAN`)](0028-query-plans.md) — **Accepted**, an `explain` prefix command over `show data` / `update` / `delete`; an annotated, span-styled plan tree; introduces the `OutputLine` styled-runs mechanism (ADR-0016's deferred per-span styling) (`QA1` / `QA2`)
- [ADR-0029 — Column constraints (NOT NULL / UNIQUE / CHECK / DEFAULT)](0029-column-constraints.md) — **Accepted**, the four column-level constraints declared in the column-spec suffix (`create table` / `add column`) and modified on existing columns via `add constraint …` / `drop constraint …`; a pre-flight dry-run guards populated columns; `CHECK` reuses the ADR-0026 expression grammar via `Subgrammar` (`C3`)
- [ADR-0030 — Advanced mode: the standard-SQL surface](0030-advanced-mode-sql-surface.md) — **Accepted**, SQL added as grammar *within the unified grammar tree* (ADR-0024), not a separate batch parser — so SQL gets the same completion / highlighting / hints / parse-errors as the DSL; mode gates the SQL forms; DDL routes through the typed `Command` executor (metadata + type vocabulary preserved), DML and `SELECT` execute as validated SQL; engine-neutral posture, the DSL→SQL teaching echo; supersedes ADR-0001's `sqlparser-rs` reservation; phased plan (`Q1` / `Q2` / `Q4`)
- [ADR-0031 — The SQL expression grammar](0031-sql-expression-grammar.md) — **Accepted**, the stratified SQL expression grammar fragment commissioned by ADR-0030 §3: a single precedence ladder (`OR`/`AND`/`NOT`, the comparison/`LIKE`/`IN`/`BETWEEN`/`IS NULL` predicate set, arithmetic incl. `||`, function calls, `CASE`) — the superset of ADR-0026's DSL `WHERE` grammar, authored as a parallel fragment so simple mode is untouched; pure validation, builds **no** AST (consumers run/store SQL as text per ADR-0030 §4/§6); reuses ADR-0026's `Subgrammar` recursion + depth cap unchanged; subquery expressions and qualified column refs deferred to ADR-0030 Phase 2
- [ADR-0032 — The full SQL `SELECT` grammar](0032-sql-select-grammar.md) — **Accepted**, the Phase-2 grammar commissioned by ADR-0030 §3: full `SELECT` with `INNER`/`LEFT`/`RIGHT`/`FULL OUTER`/`CROSS` joins, `GROUP BY`/`HAVING`, all four set ops (`UNION`/`UNION ALL`/`INTERSECT`/`EXCEPT`), `WITH` and `WITH RECURSIVE` CTEs, `LIMIT … OFFSET`, `DISTINCT`, `t.*`, and bare-alias projection (lifting Phase-1 §4.2); additive extensions to ADR-0031's `sql_expr` for scalar subqueries, `IN (SELECT …)`, `[NOT] EXISTS`, and qualified column refs (redeeming ADR-0031 §7 OOS-1/OOS-2); grammar-recursion via `Subgrammar(&SQL_SELECT_COMPOUND)` reuses ADR-0026's `MAX_SUBGRAMMAR_DEPTH = 64` cap unchanged; **softens ADR-0030 §8's "ambient assistance comes for free" claim**: completion scope needs new `WalkContext` accumulators (a `from_scope_stack` of `ScopeFrame`s holding `from_scope` / `cte_bindings` / `projection_aliases`), a **new walker node variant `Node::ScopedSubgrammar(&Node)`** as the push/pop trigger (existing `Node::Subgrammar` unchanged so DSL `Expr` and `sql_expr` recursion are unaffected), qualified-prefix completion narrowing, body-projection-derived CTE column resolution (so `SELECT *` and explicit-projection CTE bodies both yield real column completion past `cte_alias.|`), and a **post-walk fixup pass** that re-resolves projection-list identifier highlighting/validity once `FROM` is parsed (the projection-before-FROM problem); classifies every Phase-2 validation case against ADR-0027's ERROR/WARNING guideline (§11): five new `diagnostic.*` keys for parse-time-detectable cases (unknown qualifier, ambiguous column, projection-alias misplaced, CTE/compound arity mismatch) plus eight `engine.*` translation keys; a MatchedPath-walking predicate-warnings variant that closes the Phase-1 gap where SQL `WHERE` expressions emitted no `LIKE`-on-numeric / `= NULL` / type-mismatch warnings (ADR-0027 Amendment 1 finally extends to the SQL surface); adds a worker-side post-prepare type-resolution pass via engine column-origin metadata so bare column refs recover their playground type (partially lifting Phase-1 §4.5, the bool→0/1 case) — `Cargo.toml` gains `column_metadata` to rusqlite features (verified against pinned 0.39.0); `__rdbms_*` rejection extended to every new table-source slot; Amendment 1 narrows §12's resolution rule from a grammar-side structural classification to "trust the engine's column-origin metadata verbatim" after an empirical probe showed origin metadata follows through non-recursive CTEs, scalar subqueries, derived tables, set ops, and joins — the one structural exception is recursive CTE result columns, which return None and stay typeless; Amendment 2 records that §10.6's "rewrite the highlight class" prescription is realised via the two-pass schema-existence diagnostic + the renderer's diagnostic-overlay path (no separate per-byte rewrite step needed; no new HighlightClass variant), and that the projection-before-FROM completion narrowing has been improved by an `src/completion.rs` look-ahead probe when the leading walk's `from_scope` is empty but the full input parses
- [ADR-0033 — The full SQL DML grammar (`INSERT` / `UPDATE` / `DELETE`)](0033-sql-dml-grammar.md) — **Proposed**, the Phase-3 grammar commissioned by ADR-0030 §3: single- and multi-row `INSERT` (incl. `INSERT … SELECT` recursing through ADR-0032's `SQL_SELECT_COMPOUND`), `UPDATE` with `SET` assignment list, `DELETE`, all three optionally followed by `RETURNING projection_list`, plus full `ON CONFLICT … DO NOTHING / DO UPDATE` UPSERT on INSERT; **fixes the DSL-vs-SQL dispatch architecture for shared entry words (`insert`/`update`/`delete`)**: SQL-first / DSL-fallback in Advanced mode via a `Choice(SQL_shape, DSL_shape)` per shape, gated by a new walker capability `Node::Guard(fn)` — a zero-byte-consumption gating node that fails the enclosing Seq with a `ValidationError`; carries `Command::SqlInsert` / `SqlUpdate` / `SqlDelete` variants and `do_sql_*` worker handlers each of which knows the target table (for re-persistence) and the `returning: bool` flag (for DataResult routing); `shortid` auto-fill mirrors the DSL `do_insert` mechanism via worker post-fill; SQL DELETE produces the same per-relationship cascade summary the DSL DELETE does (ADR-0014 parity), with the WHERE-clause source bytes re-injected into per-child pre-count subqueries; three new walker diagnostics (`insert_arity_mismatch` ERROR, `auto_column_overridden` WARNING, `not_null_missing` WARNING) with positive + negative tests each; OOS list explicitly carves out `DEFAULT VALUES` (the project's planned seed feature), SQLite-specific `OR REPLACE` / `OR IGNORE` / `OR ABORT` / `OR FAIL` / `OR ROLLBACK` prefixes, `UPDATE FROM` multi-table updates, and WITH-prefixed DML; the `excluded` keyword inside `ON CONFLICT DO UPDATE` is a deliberate carve-out from ADR-0030 §7's engine-neutral posture (no standard-SQL UPSERT spelling exists that SQLite and PostgreSQL share); eleven phased sub-phases each with explicit exit gates + written DA gate, opening with `Node::Guard` mechanism scaffolding before any DML grammar lands; initial DA review recorded seven critiques that were resolved before status moved to Proposed
