# History

Operations on the journal, a table's versions, the change feed and webhooks: undo, time travel, restore and vacuum.

## Operations

- [Revert a journaled table operation by its `migration_id`. Refused (nothing written) when any](https://datanotes.dev/api/operations/undo_migration/): `POST /datanotes/operations/undo_migration/`
- [The operation journal, newest first: `total` (the matching operations) and `migrations`, each with](https://datanotes.dev/api/operations/list_migrations/): `POST /datanotes/operations/list_migrations/`
- [DESCRIBE HISTORY: the table's versions, newest first — `version`, `timestamp`, `operation`](https://datanotes.dev/api/operations/describe_history/): `POST /datanotes/operations/describe_history/`
- [Change data feed between two versions (both included, end defaults to latest): one entry](https://datanotes.dev/api/operations/table_changes/): `POST /datanotes/operations/table_changes/`
- [Change feed across all tables: numbered row changes (`seq`), oldest first, from engine writes](https://datanotes.dev/api/operations/list_changes/): `POST /datanotes/operations/list_changes/`
- [Webhooks of the change feed: id, url, filter (tables, ops, columns, exclude_actor), `cursor` (last change delivered), `status` (ok, failing, disabled), `last_delivery`, `last_error`. Secrets are not shown.](https://datanotes.dev/api/operations/list_webhooks/): `POST /datanotes/operations/list_webhooks/`
- [Push row changes to a URL (a service that would rather be called than poll `list_changes`): batches of up to 100 events POSTed as `{webhook, events, last}`, signed with `X-Datanotes-Signature: sha256=<HMAC of the body>`, retried with backoff until a 2xx. Events are those of `list_changes` (hand edits with their `violations`; the hand edits the service has seen are recorded before it stops). Starts from now unless `since`. Returns the webhook with its `secret` — shown only here: give it to the receiver. Only on the user's explicit request: a webhook sends the database's changes (and, with `since`, its past ones) to that address.](https://datanotes.dev/api/operations/create_webhook/): `POST /datanotes/operations/create_webhook/`
- [Stop and remove a webhook (by `id` from list_webhooks).](https://datanotes.dev/api/operations/delete_webhook/): `POST /datanotes/operations/delete_webhook/`
- [RESTORE TABLE to a `version` or `timestamp`: rows and definition return to that state —](https://datanotes.dev/api/operations/restore_table/): `POST /datanotes/operations/restore_table/`
- [RESTORE DATABASE to a `timestamp` (each table as of its last version committed at or before it) or](https://datanotes.dev/api/operations/restore_database/): `POST /datanotes/operations/restore_database/`
- [Delete transaction-log history older than `retain_from_version` (default: keep only the](https://datanotes.dev/api/operations/vacuum_table/): `POST /datanotes/operations/vacuum_table/`