GNUstep Database Library v1

SOPE contains a fork of the GNUstep Database Library (GDL) v1.0 which is used primarily by 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.