This paper describes the basic data model of an object-oriented database and the basic architecture of the system implementing it. In particular, a secondary storage segmentation scheme and a transaction-processing scheme are discussed. The segmentation scheme allows for arbitrary clustering of objects, including duplicates. The transaction scheme allows for many different sharing protocols ranging from those that enforce serializability to those that are nonserializable and require communication with the server only on demand. The interaction of these two features is described such that segment-level transfer and object-level locking is achieved.

Software is multidimensional but the tools that support it are not. The lack of tool support causes the software artifacts representing different dimensions to evolve independently and inconsistently. In order to support the evolution of multidimensional software, an environment must ensure that the different dimensions evolve concurrently. This can be accomplished through an integration framework that maintains consistency of the different dimensions as they evolve. We have build a prototype of such a mechanism by setting up and maintaining constraints among artifacts representing the different software dimensions. This paper describes that prototype and our experiences with it to date. 1

We have built a software development environment that uses constraints to ensure the consistency of the different artifacts associated with software. This approach to software development makes the environment responsible for detecting most inconsistencies between software design, specifications, documentation, source code, and test cases. The environment provides facilities to ensure that these various dimensions remain consistent as the software is written and evolves. This paper describes the techniques that underlie the environment, concentrating on those that deal with the diversity of artifacts the environment supports and on the definition and incremental maintenance of constraints between these artifacts. 1.

Conceptual programming means having programmers work directly with their models of how their system is put together. It means providing them with the means for designing, coding and maintaining systems on a computer using the pictures and text they normally use on paper. An environment for conceptual programming requires flexibility to support a wide range of languages and graphics to support languages based on pictures. The GARDEN system is a prototype conceptual programming environment that uses an object-oriented framework to meet these requirements. 1.