Berkeley-Database alike databases

Hi everyone,

I'm looking for a database management system based in the same
principles as BerkeleyDB, but with a less restricitive license (LGPL,
for instance). I found many of them on the internet:

- Tokio Cabinet
- Gdbm
- ...

But none of these supports what I call myself "partial data access
operations". By that I mean the ability to, given a certain key K,
fetch or store just a part of the data associated to that key (say,
just N bytes after offset M). As far as I know, only latest versions
of BerkeleyDB offer such feature.

Thanks in advance,
Emilio.