Abstract

We are currently deslgnlng a class modlficatlon methodology for Gemstone. We describe the current status of the design. We choose from two basic approaches and then introduce those aspects of Gem- Stone necessary for an understanding of the paper. After defining a set of invariants for Gemstone data- bases, we discuss specific class modification operations in terms of maintaining these invariants. We next discuss several issues that impact class modification. These issues include concurrency and authorization, and lead to difficult choices.