M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Proc. of Intl. Conf. on Very Large Data Bases, pages 34--42, 1983.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....System R allows the user to define special triggers in the form of assertions. Assertions are SQL predicates that the system enforces against all updates to the database. Assertions can be triggered by any update that can change the value of a predicate. The term active databases was coined in [Mor83], which presented a system that could support automatic update of derived data and views when base data is updated. Previous work on enhancing a DBMS has mostly been on adding some type of rule based technique to the database. Rules have been shown to be useful for specifying constraints etc. ....

M. Morgenstern. Active Databases as a Paradigm for Enhanced Computing Environments. In Proc. of the 9th International Conference on VLDB, pages 34-42, 1983.

....are also presented. The discussion is based on Heraclitus[Rel] an imperative language containing a relational calculus sublanguage and deltas. 1 Introduction Active databases generally support the automatic triggering of updates as a response to user requested or systemgenerated updates [M83] Many active database systems, e.g. CC 90, Coh86, Coh89, MD89, H89, SdM88, SIG89, SJ 90, WF90, ZH90] use a paradigm of rules to generate these automatic updates, in a manner reminiscent of expert systems. As discussed in [HJ90] and elsewhere, each This research was supported in part ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. Proc. of Intl. Conf. on Very Large Data Bases, pages 34--42, 1983.

....processes to be controlled and conducted according to business standards, policies and procedures [21] This was only the start. Later, IS researchers and practitioners started to work on business rules from various perspectives. Extensive research has been done in relation to active databases [17, 18, 19, 20]. Using active components, like triggers and database procedures, active databases per form their own data integrity functions instead of letting the integrity be managed by the application code. It appeared soon that active databases could be used as an instrument to enforce business rules. In ....

M. Morgenstern, "Active Databases as a Paradigm for Enhanced Computing Environments", Proc. of the 9th International conference on Very Large Databases, pp. 34-42. Florence, Italy, 1983.

....cultural and historical biases might also have had a role in this chasm, the root of the problem is actually technical and can be traced to certain semantic inadequacies in both approaches. Several active database languages and systems have been proposed so far: a very incomplete list include [3, 5, 9, 19, 20, 29]. However, there is is no unifying semantic theory for active databases: most of the work done so far has concentrated on explaining operational semantics of particular systems. On the contrary, deductive databases are endowed with extraordinarily rich semantic foundations: not one but three ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Ninth International Conf. on Very Large Data Bases, Florence, pages 34--42, 1983.

....biases share the blame for this chasm, the root of the problem is actually technical and can be traced to certain semantic inadequacies in the conceptual foundations of both approaches. Several active database languages and systems have been proposed so far: a very incomplete list include [1, 3, 8, 9, 14]. However, there remains a dire need for clarifying and formalizing the semantics of these systems [18, 19] The situation for deductive databases appears to be just the opposite, since not one but three equivalent formal semantics have been developed for Horn clauses [16, 7] Unfortunately, this ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Ninth International Conf. on Very Large Data Bases, Florence, pages 34--42, 1983.

....of the existing data are not provided. Research on active databases is motivated by the need for a database management system to automatically monitor and react to real world (or external) events as well as database states and constraints. Research efforts on this subject have been reported in [MOR83, STO85, DIT86, HSU88, DAY88a, DAY88b, CHA90, BEE91]. However, the specifications of triggers and conditions associated with rules (e.g. the condition part of HiPAC s ECA rules) in these research are limited to the current information because of the lack of a mechanism for managing and processing temporal data. In many advanced applications such ....

Morgenstern, M., "Active Databases as a Paradigm for Enhanced Computing Environments", Proc. of the Int'l Conf. on VLDB, 1983, pp. 34-42.

....M g and generate data and operations for each local environment. Whenever the transition of the global environment changes from one state to another, all ECA rules defined for that new state are executed automatically and the new local environments are created dynamically. 6. Related Work In [15], the author has discussed a framework for managing the interactions between the work environments using active databases. Available data in the working environment includes articles, programs and documents. Interaction between environments require descriptions to express database updates and ....

M. Morgenstern. Active Databases as a Paradigm for Enhanced Computing Environments. In Proc. of the 9th VLDB Conference, pages 34-42, 1983.

....two deltas; capturing this intuition would require a property that is model dependent. 6 Active Database Execution Models Active database technology offers a relatively declarative style of specifying database behavior. Triggers are the most primitive form of activeness; these were enriched in [Mor83] by considering rules with more complex conditions, possibly referring to more than one (virtual) state of 36 the database. Since then, a host of active database systems have been proposed in the literature, along with considerable research demonstrating the promise of activeness in connection ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Proc. of Intl. Conf. on Very Large Data Bases, pages 34--42, 1983.

....3 Special Issues In the following we group the publications according to various issues in the context of active database systems. 3. 1 Initial Reading Recommended for initial reading in the field of active database systems or special topics are: References: Cha93] Day88] DG93] HW93] Mor83] VK93] 3.2 Comparisons of Approaches The following papers give overviews and comparisons of different active database systems and solutions: References: Cha93] Day88] DG93] HJ91] HW93] PDW 93] VK93] ZB90] 3.3 Underlying Data Model This subsection distinguishes the ....

....in: References: Cha92] CZ93] Jas94] 3. 8 Implementation Issues There are prototypes implemented, and the following papers discuss details of implementations: References: Car92] CKAK93] CN90] Coh89] DM89] GD93b] GJS92a] Han92b] Han92a] HB91] HK87] HK89] KD93] Mor83] RCBB89] WCL91] 3.9 Optimization Optimization of rule execution spans from efficient event detection to efficient data condition evaluation to fast and non redundant rule action execution. References: AVG92] BGLM91] BM93] Cha89] CHS92] CN90] CZ93] DPG91] FRS93] HK89] ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Proc of the 9th Int'l. Conf. on Very Large Data Bases, Florence, November 1983.

....updates. Many active database systems, e.g. CCCR 90, Coh86, MD89, Han89, dMS88, SIG89, SJGP90, WF90, ZH90] use a paradigm of rules to generate these automatic updates, in a manner reminiscent of expert systems. Active databases have been shown useful for constraint maintenance [Mor83, CW90, HJ91a] incremental update of materialized views [CW91] query rewriting [SJGP90] database security [SJGP90] and hold the promise of providing a new family of solutions to the view and derived data update problem [CHM92] and issues in heterogeneous databases [CW92] Active database ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Proc. of Intl. Conf. on Very Large Data Bases, pages 34--42, 1983.

....As described in Chapter 3, rules are used extensively in STRIP s architecture as a means to implement core functionality. For example, rules are used to maintain the materialized views and for some importation and exportation tasks. One of the first papers to suggest using rules in this manner was [Mor83]. In this study, dynamic views are maintained by application provided procedures called demons that are invoked when the database changes. Hence the demons are the actions triggered by data modification events. More recently, Ceri and Widom [CW91] explored the use of rules to maintain views in ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Proceedings of the 9th VLDB Conference, pages 34--42, 1983.

....that they preserve database consistency. Furthermore, materialized views [Dat86] must be updated whenever they are affected by database updates. This could be done incrementally by the database manager. The term active databases was first used to denote such databases incrementally updating views [Mor83] Later, active databases have come to denote much more than that, for example triggering facilities, constraint checking, etc. Today, we define an active database as a database being able to react to events and conditions in the database, or even the surrounding applications and environment. The ....

....of the ideas that appear in active database systems are not new. The ON Clause in CODASYL [Com73] implemented a simple trigger facility in which a data manipulation language operation triggered a database procedure which was executed immediately. The term active database was first used in [Mor83] to denote mechanisms for automatic view updates and consistency maintenance. In [Sto86] triggers were further developed as a means for implementing alert functions and keeping constraints in a relational database management system. These ideas were implemented in POSTGRES [SRH90] Other ....

Matthew Morgenstern. Active databases as a paradigm for enhanced computing environments, 1983.

.... for a number of useful database tasks: they can enforce integrity constraints, implement triggers and alerters, maintain derived data, enforce access constraints, implement version control policies, gather statistics for query optimization or database reorganization, and more [Eswaran 1976, Morgenstern 1983, M. Stonebraker 1982] Previous support for these features, when present, provided little generality and used special purpose mechanisms for each. In addition, the inference power of production rules makes active database systems a suitable platform for building large and efficient knowledge base ....

Morgenstern, M. (1983). Active databases as a paradigm for enhanced computing environments. In Proceedings of the Ninth International Conference on Very Large Data Bases.

.... DBMS technology [5, 14, 22] Parallel data servers aim to achieve high performance by exploiting maximum parallelism using multiprocessor architectures [14, 47] The main feature of an active DBMS is to react autonomously (without user intervention) to different events that can occur in a DBMS [16, 30, 29]. The main goal of an object oriented DBMS is to model and process the structural and behavioral properties of complex real world objects naturally and efficiently [4, 44, 5] Although significant research has been carried out in the above areas separately, little attention has been given to the ....

M. Morgenstern. Active Databases as a Paradigm for Enhanced Computing Environments. In Proceedings 9th International Conference on Very Large Data Bases, pages 34--42, 1983.

....the colloquia chairman about some talks they scheduled. This inconsistency has lead to dissemination of inaccurate information and scheduling of multiple talks at the same time. Some of these problems of manual management of group activities are well known and mechanisms such as active databases [20] and next generation databases [29] have been proposed to build applications that address the problems. However, we know of no application built using these mechanisms that addresses all of these problems. Therefore, we decided to experiment with the engineering of such an application, thereby ....

M. Morgenstern, "Active Databases as a Paradigm for Enhanced Computing Environments," Proceedings of the 9th International Conference of Very Large Data Bases , 1983, pp. 34-42.

....updates. Many active database systems, e.g. CCCR 90, Coh86, MD89, Han89, dMS88, SIG89, SJGP90, WF90, ZH90] use a paradigm of rules to generate these automatic updates, in a manner reminiscent of expert systems. Active databases have been shown useful for constraint maintenance [Mor83, CW90, HJ91a] incremental update of materialized views [CW91] query rewriting [SJGP90] database security [SJGP90] and hold the promise of providing a new family of solutions to the view and derived data update problem [CHM92] and issues in heterogeneous databases [CW92] Active database ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Proc. of Intl. Conf. on Very Large Data Bases, pages 34--42, 1983.

....systems. Finally, section 6 presents conclusions and directions for future work. 2 Active Database Systems and Constraint Support Active databases are systems that respond to events generated internally or externally to the system itself without user intervention. The term active appeared in [Mor83] to describe a database that supports automatic view modifications to reflect updates to the underlying database. Nowadays, the active dimension is usually supported by production rule mechanisms, provided by the DBMS. The term rule is associated with the notion of production rules which are ....

....their manipulation (query, update, activation and deactivation of rules) The paradigm of active databases is useful for implementing or extending several database functions. Some examples are integrity control, handling of derived data, processing of view updates, and monitoring of events (e.g. Mor83, Mor84, Ris89, RCBB89, MD89] Most of the published research on active databases discusses the support of static integrity constraints using E,C,A rules. In such a framework, rule components have the following meaning: the Event is an update request; the Condition is the constraint s ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Proc. 9th VLDB, pages 34--42, 1983.

....systems. A number of potential uses motivate the addition of such a facility. Production rules are a natural mechanism for integrity constraint enforcement, as suggested by [Esw76] More generally, production rules permit additional semantic structure for the database. In active database systems [MD89, Mor83], production rules are used to monitor particular conditions (sometimes associated with timing constraints) and, when appropriate, to trigger corresponding actions. Esw76] suggests that production rules may be useful for authorization checking and for maintenance of derived data. Finally, ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Proceedings of the Ninth International Conference on Very Large Data Bases, pages 34--42, Florence, Italy, October 1983.

....T 1 T 2 ) s 1 s 2 Reasoning is then performed by instantiating meta level clauses defining axioms of the knowledge base [Sri93] The times at which propositions are taken to be true are obtained from the specification of event occurrences. Active Rules The emergence of active database systems [Mor83] Day88] made possible the specification of reactive behaviour in databases. Integrity constraints can be specified and enforced by means of rules whose execution is triggered by the occurrence of events. Production rules [CFPT92] CFPT94] FP92] or Event Condition Action (ECA) rules [Kot88] ....

Matthew Morgenstern. Active Databases as a Paradigm for Enhanced Computing Environments. In Proceedings of the 9th International Conference in Very Large Databases, pages 34--42, 1983.

.... rules in database systems allow specification of data manipulation operations that are automatically executed whenever certain events occur and or certain conditions are met [DE89, Han89,KdMS90,SJGP90,WF90] The usefulness of incorporating production rules into database systems is well accepted [EC75,MD89,Mor83], particularly in the context of constraint enforcement. However, we know of no automatic (or semi automatic) method for specifying general constraints in a high level, non procedural language, then deriving lower level production rules that maintain the constraints. We describe such a method. The ....

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Proc. of Ninth VLDB, pages 34--42, October 1983.

....can be incrementally maintained as user defined priorities are altered. We also discuss how the proposed scheme can be extended to build a multi level hierarchical priority system. 1 Introduction Incorporation of production rules into database systems has recently received considerable attention [6, 7, 8, 11, 19, 21, 25, 26, 27, 30]. A central issue in production rule systems is conflict resolution [20, 14] Given that two or more rules are triggered, a conflict resolution mechanism determines which rule is considered first for execution. Some rule systems (for example, Postgres Current address: Computer Science ....

M. Morgenstern. Active Databases as a Paradigm for Enhanced Computing Environments. In Proc. 9th International Conference on Very Large Data Bases, pages 34--42, Florence, Italy, October 1983.

No context found.

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Proc. of Intl. Conf. on Very Large Data Bases, pages 34--42, 1983.

No context found.

Morgenstern, M. (1983). Active databases as a paradigm for enhanced computing environments.

No context found.

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Ninth International Conf. on Very Large Data Bases, Florence, pages 34-- 42, 1983.

No context found.

M. Morgenstern. Active databases as a paradigm for enhanced computing environments. In Ninth International Conf. on Very Large Data Bases, Florence, pages 34--42, 1983.

First 50 documents

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC