Active object-oriented database management systems incorporate object-oriented database technology and active mechanisms such as event-condition-action rules (ECA-rules). SAMOS has been among the first representatives of this class of systems. During the development of SAMOS, numerous then open research questions have been addressed. In this paper, we… (More)
SAMOS is an active object-oriented DBMS implementing " reactive behavior " by detecting situations in the database and its environment and performing user-specified actions. SAMOS extends an object-oriented DBMS with active feat ures (1]. It provides a rule definition language as a means to specify ECA-rules including constructs for the definition of… (More)
This paper describes the active, object-oriented database system SAMOS being developed as a research prototype. Its main approach is the integration of rules in the sense of active database systems into a general object-oriented data model. Our effort is also focussed on integrating the rule system with transaction processing in a meaningful way.
Interoperability and integration of data sources are becoming evermore important issues as both, the amount of data and the number ofdata producers are growing. Interoperability not only has toresolve the differences in data structures, it also has to dealwith semantic heterogeneity. <i>Semantics</i> refer to the meaningof data in contrast to syntax, which… (More)
This paper deals with the problem of handling semantic heteroge-neity during schema integration. Semantics refer to the meaning of data in contrast to syntax, which solely defines the structure of schema elements. We focus on the part of semantics related to the meanings of terms used to name schema elements. Our approach does not rely on the names of the… (More)
This paper presents market-based workflow management, a novel approach to workflow specification and execution which regards activities contained in a workflow as goods traded on an electronic market. Information about expected cost and execution time is considered for activity specifications, and is used at runtime to execute workflows such that actual… (More)