@sharesync/sharedb-mysql

MySQL database adapter for ShareDB (the ShareSync fork) — the main backend op/snapshot store, following the sharedb-mongo naming convention.

Not a DurableStore adapter. The @sharesync/sharedb-storage-* packages are client-side offline stores; this package is the authoritative database behind a ShareDB server.

Usage

var ShareDB = require('@sharesync/sharedb');
var ShareDBMySQL = require('@sharesync/sharedb-mysql');

var db = new ShareDBMySQL({uri: 'mysql://user:pass@host:3306/mydb'});
// or share an existing mysql2/promise pool (the adapter won't close it):
// var db = new ShareDBMySQL({pool: myPool});
// or mysql2 pool options:
// var db = new ShareDBMySQL({connection: {host, user, password, database}});

var backend = new ShareDB({db: db});

Schema

Two tables — an append-only op log keyed (collection, doc_id, version) and one snapshot row per doc. They are created automatically on first use; pass ensureTables: false and run schema.sql yourself if your deployment separates DDL from runtime (the statements are also exported as ShareDBMySQL.DDL).

Semantics

• Concurrency control is the op log's primary key. ShareDB's commit() contract — exactly one of two racing submissions at a version may succeed — is enforced by the duplicate-key rejection on the op insert, inside a transaction with the snapshot write.
• A document's version is its op count (the MemoryDB reference semantics): a deleted document still reports the version implied by its op log.
• No live queries. query() is unimplemented on purpose; keep your queryable state in your own tables and use this adapter as the op/snapshot store.
• Snapshot data distinguishes no data (SQL NULL → undefined) from JSON null (stored as JSON null).

Tests

Runs the ShareSync fork's own pluggable DB acceptance suite plus MySQL-specific tests (commit races, JSON-null round-tripping):

MYSQL_TEST_URI=mysql://root@localhost:3306 npm test

The test database (sharedb_mysql_test) is dropped and recreated per run.

License

MIT