Small relational DBMS?

[KiYun Roe]

I am looking for a Unix-based relational DBMS to be used for a
relatively small application.  The total amount of relational data at
any one time will be on the order of several megabytes, but new data
and new tables will be generated often.  I am especially interested in
a system that makes it easy to create new columns from existing ones
using simple mathematical operators and functions.  The usual
relational operators should be supported: select, project, join, diff,
etc.  It should be possible to generate reports sorted on arbitrary
columns.  Most queries will be relatively simple, but the select
operator should support fairly complex conditions.

The problem is that the big commercial offerings like Informix, Unify,
Ingres, and Oracle are overkill for my application.  They are suited
for the development of high-performance, relatively fixed applications,
but I am more interested in a flexible tool for manipulating data that
falls in the relational model.

Any pointers will be appreciated, whether to commercial or
non-commercial offerings.
--
KiYun Roe					kroe at sbcs.sunysb.edu
Department of Computer Science
SUNY at Stony Brook
Stony Brook, NY  11794-4400			(516) 632-7675