Legacy Redland storage plug-in disposition (0.4)

Milestone: 0.4
Status: accepted

Historical Redland librdf storage factories are not reproduced as native Oxiland backends. Callers that request these names receive Error::Unsupported with migration guidance.

Redland name (typical)	Disposition	Guidance
memory	Supported	Model::new
hashes / file hashes	Unsupported	Use Model::open (Fjall) or N-Quads archive
file	Unsupported	Export/import N-Quads or TriG
mysql	Unsupported	Dump to N-Quads; load with Oxiland I/O
postgresql / postgres	Unsupported	Dump to N-Quads; load with Oxiland I/O
sqlite	Unsupported	Dump to N-Quads; load with Oxiland I/O
tstore	Unsupported	Dump to N-Quads
uri	Unsupported	Fetch RDF externally; parse with Parser
virtuoso	Unsupported	SPARQL/GRAPH export → N-Quads
rocksdb / redb	Unsupported	Replaced by Fjall (Model::open)

Oxiland’s durable backend name is fjall. Backend names must never silently select a different persistence technology (project charter).

Archival path

Prefer standards RDF for longevity:

1. Model::export_nquads_to_path / Serializer (TriG when needed)
2. Upgrade Oxiland
3. Model::import_nquads_from_path or Parser::load_transactional

Binary Fjall directories are an Oxiland format v1 working store, not a cross-vendor archive format.