# MIGRATION_IRREVERSIBLE

A migration to roll back has no `-- DOWN` section.

## Cause

A migration to roll back has no `-- DOWN` section.

`nextly migrate:down` runs the `-- DOWN` section of each migration it rolls back. This file's is empty, so there is no way to undo it.

## Fix

* Hand-write a `-- DOWN` section that undoes the file's `-- UP` statements, then run the command again.
* Or, on a development database, use `nextly migrate:fresh`.

See [Production migrations](https://nextlyhq.com/docs/guides/production-migrations.md).

## Example

```text
✗ 20261020_120000_add_posts.sql has no down SQL — it is irreversible.
  Why:  `nextly migrate:down` runs a migration's `-- DOWN` section, and this file's is empty.
  Next: Hand-write a -- DOWN section or use 'nextly migrate:fresh'.
  Docs: https://nextlyhq.com/docs/cli/errors/migration-irreversible  (MIGRATION_IRREVERSIBLE)
```