Your question was a little lacking in details, so I can only answer part of your question. When you post the logs from your terminal, I can answer the rest.
How can I force the db to be updated?
-yy switch to
pacman forces it to refresh the DBs from the internet, even if they're not out of date. Use e.g.
pacman -Syyu to update your system with fresh DBs.
In subsequent comments, you've stated that
pacman just printed 0%, with a progress bar, and continued on its merry way. This probably means you have a corrupted DB on the local disk. In that case, just do a
pacman run using
-yy and you should be fine.