When you search in a database with one text field and with no entries you get the error: moodle_database::get_in_or_equal() does not accept empty arrays.

To reproduce:
1. Create a new Database, with a text input field, or a text area field.
2. Don't Add any entry
3. Search the text or text area
4. Got the error message: Coding error detected, it must be fixed by a programmer: moodle_database::get_in_or_equal() does not accept empty arrays

Work around:
The Database creator should input a dummy text first, before someone keen to search, even they can't see anything in the list view, knowing nothing to search.