Open architecture ILS?

[Karen Harker <Karen.Harker@UTSouthwestern.edu>]

I'm a librarian by trade, but have been developing Web applications for our library for a couple of years.  Lately, I've become frustrated by our ILS (Unicorn), mainly in the inability to openly communicate with it.  We have a wonderful patron database that is inaccessible from anywhere except Unicorn. We cannot link to pre-defined searches (i.e. New Books, all books on molecular biology of lung cancer, etc.). These are the two main examples. 

It all boils down to the fact that Unicorn is a closed system - only Unicorn modules can access the data. Being uneducated in computer science, is this what is referred to as "closed architecture"?

No matter what it's called, what are some good systems out there that, at the very least, use a database that can be queried with SQL (i.e. Oracle, MS SQL (I know...forgive me), etc.)?  

Thanks.
Karen R. Harker
UT Southwestern Medical Library
Dallas, Texas