Open Basecamp with alternate database?

I don't know of any command line options but have seen the option to add a database and select the one you want.  It is in Edit > Options > General > Database options.  I have never used this feature.

As posted, BaseCamp allows you to run different databases, why would you need a command line function?

I understand the inquiry by the OP.  It would be a whole lot easier to specify the database at startup rather than changing it within Basecamp.  Heck, I have several File Explorer desktop shortcuts that immediately open a specific directory instead of having to navigate to it.  It's just easier.

Desktop shortcuts I understand, it's using command line functions that surprise me, computers have moved on a long way since it was necessary to use those

Nobody said anything about "necessary".  First, a desktop shortcut nothing more than a command line executed by a desktop icon.  Its simplest form is a path to the desired executable (a command line) but it can be so much more when options can be passed to the executable from the command line.  Second, suppose I always run Basecamp and an online mapping service simultaneously.  I would create a script that started both and have a desktop shortcut to that script.  That is three command lines utilized solely for the purpose of convenience.  Sure, it isn't necessary, but it beats the heck out of starting Basecamp, then starting a browser, then navigating to the mapping service.

Guess you're knowledge is way beyond most of us. I'd have no idea how to create three command lines etc

Thankfully Microsoft and Windows removed the need for most of us to learn that stuff.

I had not seen that option, so that's one way... but I'm looking to have two shortcuts on my desktop: one for hike one for bike - and then I just click on the one I want to open.  The Database Option would require me to open BC, go to options, choose the other DB, restart BC, etc...  Thanks for letting me know about that feature though.

Yes, this.

You understand, thank you.