What determines when Calibre updates the metafile in a file, versus in its database? Experimental evidence seems to indicate the following:
* Updating fields in the DB will not update any existing files.
* Converting a file from one format to another writes the database metadata to the new file, rather than grabbing it from the original file "as is".
(OPF metadata not represented in the database will be copied over, at least from LIT to ePub - though since I don't have SQLite set up, I don't know if these are stored-but-hidden or actually copied at conversion time.)
* Sending a file to a device usually updates the metadata (but not always - fields blank in the database but set in the file will not be cleared).
Does this sound correct? I've already accepted that I'm going to have to nuke-and-burn my existing Calibre DB, but I want to make sure that I design it "right" around my needs when I'm rebuilding it.
