The fourth constraint. `check ( <expr> )` reuses the ADR-0026
WHERE-expression grammar via `Subgrammar`, so a check is
written in the same language as a `where` filter.
- Grammar: a `CHECK_CONSTRAINT` arm joins the shared
constraint-suffix Choice; `consume_check_expr` extracts the
parenthesised expression (paren-depth aware) into
`ColumnSpec.check` / `Command::AddColumn.check`.
- Storage: the parsed `Expr` is compiled once to inline SQL
(`compile_check_sql` — `compile_expr` + ADR-0028's
param-inliner) and stored in that form everywhere — a new
`check_expr` column in `__rdbms_playground_columns`,
`project.yaml`'s `ColumnSchema.check`, and the column DDL
emitted by `do_create_table` / `schema_to_ddl`.
- `add column … check` routes through the rebuild primitive
(SQLite's `ALTER … ADD COLUMN` cannot carry it); a CHECK on
a serial/shortid column is create-table-only and refused at
add-column with a friendly message.
- `describe` surfaces the CHECK. ADR-0029 §7/§8 updated to the
SQL-form decision — double-quoted identifiers, consistent
with ADR-0028's `explain` display SQL.
1201 tests pass (+8); clippy clean.
`create table … with pk` now parses the column-constraint
suffix; combined with the commit-1 db layer, a constrained
table works end to end.
- A shared constraint-suffix grammar fragment — `not null`,
`unique`, `default <literal>` — sits after each column's
`(type)` group; `build_create_table` walks the matched path
per column and folds the constraints into `ColumnSpec`.
- §9 redundancy check: every `with pk` column is a primary-key
column, so `not null` (any) and `unique` (single-column PK)
are rejected with a friendly error
(`parse.custom.constraint_redundant_on_pk`).
- `project.yaml` round-trip: `ColumnSchema` gains `not_null` /
`default`; the YAML reader/writer and `build_read_schema`
carry them, so `rebuild` / `export` / `import` preserve
constraints.
- ADR-0029 §2.1's example corrected — `create table` columns
are all PK columns, so its suffix is for `default` / `check`;
`docs/simple-mode-limitations.md` records that non-PK
columns at create time need advanced mode.
CHECK is deferred to the next commit. 1184 tests pass (+7);
clippy clean.
Designs the remaining C3 surface: the four column-level
constraints declared in the column-spec suffix at `create
table` / `add column`, and modified on existing columns via
`add constraint … to` / `drop constraint … from`.
- A pre-flight dry-run (the ADR-0017 ethos) scans a populated
column before applying NOT NULL / UNIQUE / CHECK and refuses
with a pretty-table of offending rows; no `--force`.
- CHECK reuses the ADR-0026 expression grammar via Subgrammar.
- `__rdbms_playground_columns` carries a new `check_expr`
column; the other three are recoverable from SQLite pragmas.
- README index updated.
claude@clouddev1