# X_PATCH_EMPTY

## Means

`updateWhere()` named no columns to write

## Typical cause

an empty patch, or one whose only value came back `undefined` — reporting "n rows updated" for a statement that set nothing is the silent no-op the count exists to prevent

## Fix

name the columns to write, e.g. `db.participants.updateWhere({ conversationId, userId }, { lastReadAt })`

[Entity and database](/error-codes#entity-and-database)