Looking at dataview documentation and googling.
I want to include a WHERE clause that specifies that a file contains a given field. e.g. something like
WHERE contains(file, “rating”)
The above doesn’t work since the file object only contains implicit fields. I think the above should work if instead of file the input was some object that contains fields corresponding to the page’s dataview fields. However I haven’t been able to find any such object described in the dataview documentation.