GNUstep Database Library v1
SOPE contains a fork of the GNUstep Database Library (GDL) v1.0 which is used
primarily by OpenGroupware.org. GDL is mostly compatible with the EOF 1.1
by NeXT Computer Inc., so while it has some similiarity with newer
WebObjects EOF versions, it misses a lot of new things.
In case you are looking for an EOF 4 compatible database library which can be used together with SOPE, consider GDL 2, which is in active development.