Database changes

I have done some changes to my digiKam collections to streamline my 
images. I had two jpg folders essentially containing the same files with 
different dpi settings. I have now only one collection. Earlier the tag 
information was embedded in the files, now it has been separated to 
sidecars. These sidecars have been manipulated outside digiKam to add 
xmp ratings. However, I do not see these ratings in digiKam. Do I need 
to do any database cleanup so that the information in the sidecars and 
the information in the digiKam database matches?

mj