As a minimum, see if you've got some kind of berkely db support on your box. If you can get berkely dbm hash style dbs up and running then you don't have to worry about filling up a file system with a bunch of files and stuff like that. Berkely style dbs are used for lots of programs, like htdig, and many system apps, so it's likely that some version is already on your box.
If you don't want to use even that, then sure, you can get by without a database. You can basically treat the file system like a database itself, but you won't have the guaranteed integrity (sp?) that a heavy weight dbms like postgresl or interbase, or the ease and speed of a light weight dbms like Mysql/MSQL etc...
You can use the serialize/unserialize commands to put variables in a text readable/storable format for import/export from a text file as easy as a database.