1993cascont M.T. Özsu, R.J. Peters, B. Irani, A. Lipka, A. Munoz and D. Szafron, TIGUKAT Object Management System: Initial Design and Current Direction, CASCON 93, Toronto, Canada, October 1993, pp 595-611. abstract or pdf.
Abstract:

We describe the TIGUKAT object management system that is under development at the Laboratory for Database Systems Research of the University of Alberta. TIGUKAT has a novel object model whose identifying characteristics include a purely behavioral semantics and a uniform approach to objects. Everything in the system is a first-class object with well-defined behavior. The computational model supported is one of applying behaviors to objects. A query model has been developed for TIGUKAT that is complete with a formal object calculus, an equivalent object algebra and an object SQL language. The uniformity of the model permits modeling queries as objects, opening up the possibility of developing an extensible query optimizer. A prototype implementation of TIGUKAT, including the language and its optimizer is ongoing.