[mythtv-users] Key difference(s) between mythfilldatabase and mythfilldatabase --update?

[Nick]

I'm just wondering what the difference is between running these two
commands when using an XML source file for data (i.e. what data is
lost/preserved when run with and without the --update option).

I read in the mythfilldatabase help that --update runs non-destructive
updates on the DB, but how non-destructive is it? I.e. will it take
into account changes to program details already in the DB and update
those. What data would be lost without using the --update option.

Thanks for anyone that can clarify this. Before I try and put my C cap
on to get a definitive answer myself, I'm hoping someone can explain
it concisely.

Cheers,
Nick