How to update local zwave database?

No - I will not implement this - sorry. It means OH becomes a cloud only system (at least for ZWave) and I don’t believe that’s wise.

There are many discussions about this on the forum. I agree at the moment it’s a bit of a pain as it needs to be done manually (a bit like it was in OH1 with dropping JARs into the addons folder) but this will also be fixed soon with the introduction of the Marketplace.