# DEMOTE_COLLECTION_NOT_FOUND

`db:sync --demote` names a collection that `nextly.config.ts` does not define.

## Cause

`db:sync --demote` names a collection that `nextly.config.ts` does not define.

`nextly db:sync --demote <slug>` hands a collection defined in `nextly.config.ts` to the Schema Builder. The configuration's `collections` array has no collection with this slug.

## Fix

* Check the slug against the `collections` array in `nextly.config.ts`.
* A collection built in the Schema Builder is already there and needs no demotion.

## Example

```text
✗ Collection 'posts' not found in nextly.config.ts collections.
  Why:  `--demote` moves a collection defined in `nextly.config.ts` to the Schema Builder, and its `collections` array has none with this slug.
  Next: Check the slug against the `collections` array in `nextly.config.ts`. A collection built in the Schema Builder is already there and needs no demotion.
  Docs: https://nextlyhq.com/docs/cli/errors/demote-collection-not-found  (DEMOTE_COLLECTION_NOT_FOUND)
```