Andrea H. Skarra

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We examine the problem of type evolution in an object-oriented database environment. Type definitions are persistent objects in the database and as such may be modified and shared. The effects of changing a type extend to objects of the type and to programs that use objects of the type. We propose a solution to the problem through an extension of the(More)
2 Transaction Approach 47 2.1 A Design Task Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 2.2 Compatibility Set Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 2.3 Constraint-Based Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 2.3.1 Intuitive Model of CAD Transaction(More)
We describe a concurrency control model that supports cooperative data sharing among transactions. Setializability is replaced by applicationand data-specific coneemess criteria that are explicitly defined by programmers. The model is relevant to applications that provide computer support for cooperative activities, such as office information systems,(More)
Traditional atomic transactions do not work well in databases used by design applications. A typical design task is divided into parallel subtasks that are interdependent. We relax the constraint of atomicity in these situations to allow cooperative transactions to work together in groups to accomplish design tasks in the database. These groups may be(More)