About db file sizing

[Carlos de Luna Saenz]

I really don't know if this is a good couple questions or not...
We are developing an embedded DB app that has a 1.74GB of files for the
database
I wonder if there is something like a shrink or compact command that
will reduce the amount of space for the app DB.
Is there a way to make it user/password protected? We don't want to
"start" a server on the program side but password protection would be
appreciated.
Greetings