Build a Durable Object backed by SQLite storage, bind and address it from a Worker, query it with the SQL API, and schedule background work with alarms.

Documented steps

1. Export a class extending DurableObject from 'cloudflare:workers' with constructor(ctx, env) calling super(ctx, env); keep a reference like this.sql = ctx.storage.sql for SQL access. https://developers.cloudflare.com/durable-objects/get-started/
2. Add a durable_objects binding in the wrangler config: {"durable_objects": {"bindings": [{"name": "MY_DURABLE_OBJECT", "class_name": "MyDurableObject"}]}}. https://developers.cloudflare.com/durable-objects/get-started/
3. Declare the class as SQLite-backed. Current recommended way: the "exports" field in the wrangler config, e.g. {"exports": [{"name": "MyDurableObject", "type": "durable_object_namespace", "storage": "sqlite"}]}. The older migrations flow — {"migrations": [{"tag": "v1", "new_sqlite_classes": ["MyDurableObject"]}]} — is still supported but is now documented as the legacy path; each migration tag must be unique per Worker. Note "exports" and "migrations" are mutually exclusive in one config. https://developers.cloudflare.com/durable-objects/reference/durable-object-class-migrations-legacy/
4. From a Worker, get a stub with const id = env.MY_DURABLE_OBJECT.idFromName("some-name"); const stub = env.MY_DURABLE_OBJECT.get(id); then call RPC methods directly, e.g. await stub.sayHello(). https://developers.cloudflare.com/durable-objects/api/namespace/
5. Inside the class, query with this.ctx.storage.sql.exec(query, ...bindings), which returns a SqlStorageCursor; fully consume it synchronously (e.g. .toArray()) before any await since cursors have no snapshot isolation across await boundaries. https://developers.cloudflare.com/durable-objects/api/sqlite-storage-api/
6. Schedule future work with await this.ctx.storage.setAlarm(scheduledTimeMs) and define an async alarm(alarmInfo) handler on the class; only one alarm can be pending per object at a time. https://developers.cloudflare.com/durable-objects/api/alarms/
7. If calling setAlarm() from the constructor, first check getAlarm() to avoid clobbering an alarm already scheduled before the wake-up, since the constructor runs before the alarm handler. https://developers.cloudflare.com/durable-objects/api/alarms/
8. Run locally with npx wrangler dev, then deploy with npx wrangler deploy. https://developers.cloudflare.com/durable-objects/get-started/