[plt-scheme] connecting to a database

I'm working on a web application, and I've finally broken down and
admitted to myself that I _need_ rather than wanting a relational database
as a back-end. I don't have much of an opinion of what particular database
to use, just that I be able to perform updates and selects on it from a
recent exp-tagged mzscheme on a Linux platform.

So what exists out there? Here's what I know of:

1. David Van Horn's mysql access library
2. Ryan Culpepper's postgres access library
3. SrPersist
4. Francisco Solsona's SchemeQL, which I guess is a wrapper on top of 2
and 3

It seems that 1, 2, and 4 are very old and haven't been maintained in a
long time, and thus probably don't work with v300. SrPersist I've, uh,
never been able to successfully get working in Unix and I don't know how
well ODBC is supported on that platform anyway.

So does anybody have _any_ database working using anything in v299/300,
and if so what are you using? Is one of the drivers I thought wasn't
working with v300 actually working with it? Is there some other system I
don't know about?

I'm seriously at the point where if there's nothing that will work, I'll
implement it myself, because swigging some database connection library
can't be more work to make than it will be to implement the convoluted and
broken text-file-based super-minimal _database_ I'll have to make
otherwise. But looking at my todo list, I really would much much rather if
I could use something somebody else has already done ... :)

I'll collect responses and write something up for the Scheme Cookbook if
there's something interesting to report.

Thanks,
-jacob