I\'m developing a little project plan and I came to a point when I need to decide what local databse system to use.
The input data is going to be stored on webserver
For quick and dirty I'd go with Sql Server Compact Edition. Its an in-process implementation of Sql Server, so it doesn't require you install any other applications.
Back in the day, you'd use an Access database for this kind of thing. But Access databases kinda blow.
It wouldn't take much to upload your finished data back to the production server. If you're looking for a solution that automates that process, you'll probably need to look at hosting an instance of MySql locally and use whatever replication services it provides.