Ok, here's the deal. I have minimal "real-world" database experience so I need some help to narrow down my search for suitable candidates to use in my project. I know there are people here with significant experience in this area, so I hope I can get some good suggestions.

Here some base requirements and concerns (though I can't give details of the actual project itself right now):

-The project is for Mac OS X. So any solution has to have compatible code available - or something easy to recompile if provided in source.

-Small memory footprint while in use is nice, small HD footprint for binaries and libraries is nice.

-This is not a commerce-server or anything related, so I'd like to stay away from an active-server setup that may require a heavy infrastructure on the machine just to deal with the database stuff.

-The project is an application that will have the ability to be run and quit and needs to access the data in the database at any time while it's active.

-There will also be some type of external cron type program that will also need access to the database.

-This project will be a commercial piece of software and we're sensitive on licencing fees for such database tools. A one time fee of a few hundred or even $1000 to $2000 is not unreasonable, but something like $1 per copy of the program is not acceptable. Free is also nice.

I'm sure there are any numbers of libraries out there for accessing data, but I'd also like something that isn't going to collapse when we decide to throw more records and fields at it, something that we can easily restructure without having to start from scratch.

Any help suggesting things to look at will be appreciated. I'll also answer more questions if needed, as I don't know if I've given enough information for people to make the best suggestions yet.

Thanks.

Bruno