Schema Evolution publication categorizer

Version control is one of the important database require-
ments for design environments. Various models of ver-
sions have been proposed and implemented. However,
research in versions has been focused exclusively on
versioning single design objects. In a multi-user design
environment where the schema (definition) of the design
objects may undergo dynamic changes, it is important to
be able to version the schema, as well as version the
single design objects. In this paper, we propose a model
of versions of schema by extending our model of versions
of single objects. In particular, we present the semantics
of our model of versions of schema for object-oriented
databases, explore issues in implementing the model,
and examine a few alternatives to our model of versions
of schema.