Rename DDL: close dialect gaps, add capability flags, atomic table swap, and rename for the remaining schema objects #47

Current state

DdlGenerator already offers renameTable, renameColumn (incl. the ColumnReference overload), renameIndex, and renameConstraint with ANSI-style defaults (ALTER TABLE … RENAME TO, … RENAME COLUMN … TO …, ALTER INDEX … RENAME TO, … RENAME CONSTRAINT … TO …).

Verified per dialect (offline tests exist for the first four; H2/SQLite/DuckDB/Derby were probed live against in-memory instances):

Requirements

1. Capability flags — always checkable before rendering

Following the established pattern (DialectCapabilitiesProvider.supportsXyz() aggregated into the DdlCapabilities record via getDdlCapabilities()), add flags so a caller can always probe before calling the generator instead of interpreting a null return:

• supportsRenameTable(), supportsRenameColumn(), supportsRenameIndex(), supportsRenameConstraint()
• supportsAtomicMultiRenameTable() (see 3), supportsRenameView(), supportsRenameTrigger(), supportsRenameSequence() (see 4)

Contract: a generator method returns valid SQL exactly when its flag is true, and null otherwise — the flag and the generator must never disagree.

2. Fix the broken dialects

• Derby: override with RENAME TABLE t TO n, RENAME COLUMN t.c TO n, RENAME INDEX o TO n (all verified live); renameConstraint → unsupported.
• SQLite: renameIndex/renameConstraint → unsupported (drop + recreate is the only option).
• DuckDB: renameIndex/renameConstraint → unsupported. Document that RENAME COLUMN fails on columns carrying an index ("Dependency Error").
• ClickHouse: renameTable → RENAME TABLE a TO b; index/constraint → unsupported.

3. Atomic multi-rename / table swap

New renameTables(List<…>): default renders one statement per pair; the MySQL family overrides with a single atomic RENAME TABLE a TO tmp, b TO a, tmp TO b; ClickHouse maps to RENAME TABLE/EXCHANGE TABLES. Capability: supportsAtomicMultiRenameTable().

4. Rename for the remaining schema objects

renameView, renameTrigger, renameSequence (sequences are currently absent from DdlGenerator altogether — add create/drop alongside). PostgreSQL: ALTER VIEW/SEQUENCE/TRIGGER … RENAME TO; Oracle: RENAME / ALTER TRIGGER … RENAME TO; SQL Server: sp_rename; unsupported elsewhere → flag false.

5. Version-aware fallback for old MySQL/MariaDB

MariaDB < 10.5.2 / MySQL < 8.0 have no RENAME COLUMN; they need CHANGE old new <full column definition> — anything omitted from the definition is silently dropped, so the definition must be passed in explicitly. Add a renameColumn(TableReference, String, String, ColumnMetaData) overload (mirroring alterColumnType) and gate on productVersion, which the dialect already compares numerically elsewhere. supportsRenameColumn() stays true; without metadata on an old version the metadata-less overload returns null.

Acceptance criteria

• Every rename* generator method has a matching capability flag, exposed through DdlCapabilities.
• Offline sqlgen tests for every dialect × operation, including the unsupported (null) cases.
• Flag and generator agree for every dialect × operation combination.