blob is a dead-end type: no literal in either mode, seed-unsupported, so
a blob column can only ever hold NULL. It rode along as the engine's
fourth storage class and never got the pedagogical scrutiny UUIDs
(excluded) and compound PKs (defended) received — and there's nothing
natural to do with binary data in a TUI teaching tool. Drop it → a
nine-type vocabulary.
Records the removal scope (Type::Blob + Value/CellValue::Blob + the
base64 CSV path + completion/grammar slot + the help/hint user-facing
strings + the binder refusal, whose message also carried a "DSL"
copy-rule bug subsumed by deletion) and the backward-compat migration:
the ADR-0015 framework's first real use — a v1→v2 migrator converts
type: blob → text and forces a .db rebuild from the migrated text.
convert-to-text chosen over drop-the-column (CSV rewrites) and
refuse-to-load. Updates the ADR index.
`decimal` is stored as exact TEXT, but SQLite has no native decimal type,
so arithmetic/aggregation implicitly coerces it to an IEEE-754 double.
The computed result carries no playground type, so `sum(price * qty)`
rendered the double's full noise — `298.59999999999997` for `298.60` — a
confusing, off-topic float lesson for a teaching tool.
Add `format_real_display`: round REAL values to 15 significant figures
(a double's reliable precision) then take the shortest round-tripping
form, collapsing `298.59999999999997` to `298.6`. Wired into `format_cell`
(result-set / `show data` cells) only — the sole surface where the noise
appears, since it arises from arithmetic.
Every other f64->string path keeps full precision for semantic, not
cosmetic, reasons: CSV persistence stays byte-exact for round-trip;
`render_value` is a canonical identity key for the uniqueness dry-runs
(dry_run_unique, check_uniqueness_collisions), where rounding would
report collisions the exact-valued engine wouldn't; FK-key matching and
EXPLAIN-SQL literals likewise stay exact.
ADR-0005 Amendment 1; +7 tests.
Captures up-front design decisions for RDBMS Playground:
stack (Rust + Ratatui + SQLite), input modes, project file
format, type vocabulary, undo snapshots and replay log,
sharing/export, and testing approach. ADR-0000 establishes
the ADR practice itself and mandates index upkeep alongside
any ADR change.
claude@clouddev1