N. Paton, O. D'iaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of Active Behaviour. In N. Paton et M. Williams, editor, Proceedings of 1st Int. Workshop on Rules in Database Systems (RIDS'93), Edinburgh - Scotland, September 1993. Springer Verlag.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....5, 19] distributed systems [21, 24] and middle ware [24, 10, 22] As we already said, event processing with rich semantic can be tailored to different application needs. The rule service compiles i) classical rule execution characteristics or dimensions that have been revisited for distribution [25, 11, 9]; and ii) new dimensions for characterizing the coordination between rule managers and other components such as event managers, other rule or transaction managers. Another important aspect of our proposal is the extensibility and adaptability properties given to our services and generated (event ....

N. Paton, O. D'iaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of Active Behaviour. In N. Paton et M. Williams, editor, Proceedings of 1st Int. Workshop on Rules in Database Systems (RIDS'93), Edinburgh - Scotland, September 1993. Springer Verlag.

....5, 19] distributed systems [21, 24] and middle ware [24, 11, 22] As we already said, event processing with rich semantic can be tailored to different application needs. The rule service compiles i) classical rule execution characteristics or dimensions that have been revisited for distribution [25, 12, 10]; and ii) new dimensions for characterizing the coordination between rule managers and other components such as event managers, other rule or transaction managers. Another important aspect of our proposal is the extensibility and adaptability properties given to our services and generated (event ....

N. Paton, O. Daz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of Active Behaviour. In N. Paton et M. Williams, editor, Proceedings of 1st Int. Workshop on Rules in Database Systems (RIDS'93), Edinburgh - Scotland, September 1993. Springer Verlag.

.... while event driven rules are more procedural because they describe exactly when they should be considered (explicit triggers) 33, 34] Both are useful in an active database system; ECA rules are needed for implementing time constrained applications as well as extensions to the database system [31], while production rules provide straight forward solutions to certain problems concerning monitoring database states or integrity enforcement [33] Current active OODB systems traditionally support ECA rules only, since their implementation is more straight forward due to the message passing ....

Paton, N W, Diaz, O, Williams, M H, Campin, J, Dinn, A and Jaime, A, Dimensions of active behaviour, in: Williams, M and Paton, N, eds., Proc. 1st Int. Workshop on Rules in Database Systems, Edinburgh, Scotland, Springer-Verlag, 1994, 40-57.

....6 References . 28 3 of 31 1 Introduction Active database management systems (ADBMS) [1, 16, 19, 24, 56, 58, 59, 75] are able to react in a predefined way to specific, predefined situations occurring in the database or its environment. The execution of appropriate reactions is automated and therefore does not require explicit requests issued by users or applications. Situations are usually specified as ....

....stored as instances of class rule, so called rule objects. All the event types are objects of class event (so called event objects) Each event object maintains a list of references to objects of class rule; these rules have to be executed when this event has occurred. Other systems (e.g. ADAM [56], Ode [38] associate rules with the objects or classes on whose operations events are defined. However, this approach is feasible only for some primitive event types (e.g. method events) because only then such a rule association exists. Our approach is more general since it can be used for all ....

N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, A. Jaime. Dimensions of Active Behaviour. In [57].

....of subprocesses greatly decreases the degree of parallelism since progress in the top level process is not possible until the complete subprocess has finished. We have addressed this problem in WISE by means of interprocess communications based on event and rule based (ECA rules) 16 mechanisms [24, 31, 14]. Our approach differs from standard ECA rule management practice in that we do not use an active database system or a distributed event engine as the underlying platform. This requirement is often not practical since neither active databases nor distributed event engines are widely available ....

N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. .Jaime. Dimensions of active behaviour. In Proc. 1st Int. Wshp. on Rules In Database Systems, pp. 40--57. Springer-Verlag (1994).

....to turn the switch off. In general, it is the coupling mode that encapsulates the relationship between a parent and reaction transaction. We decompose this relationship into scheduling mode and abort dependency. While the combinations of our SMode and AMode span the coupling modes listed in [14], Immediate, Deferred, Detached Dependent and Detached Independent, our ChildParent abort mode is not reflected by any coupling mode, although in practice it may be desirable. The distinction between scheduling and abort handling can also simplify implementation in that extra scheduling modes ....

Paton, N.W., Diaz, O., Williams, M.H., Campin, J., Dinn, A. and Jaime, A. "Dimensions of active behaviour", in [13]. pp 40-57.

....in three parts: generic rules, rule templates, and specific rules for the Military Enrollment example. 4. 1 Assumptions and Notations on Active Rules In this paper, we need very few assumptions about active rules, which therefore apply to most products and research prototypes of active databases [14, 21, 25]. We assume that rules follow the Event ConditionAction (ECA) paradigm, i.e. they are triggered by specific events, include a declarative condition and a sequence of procedural actions. In the following, we use a simple notation for active rules, borrowed from [3] Rules have the following ....

Paton N.W., Diaz O., Williams M., Campin J., Dinn A., and Jaime A: "Dimensions of Active Behaviour ", in Rules in Database Systems, Norman W. Paton and M. Howard Williams (Eds), SpringerVerlag, 1993.

....In many application areas, this is a severe limitation that interferes with good programming and restricts the usability of the system. In this paper, we address the problem of incorporating interprocess communication into the PSS engine. Our approach is based on event and rule based mechanisms [13, 16] similar to those used in event based workflow architectures [4, 8] However, we do not necessarily rely on active database technology to implement our solution. Part of this work has been funded by the Swiss National Science Foundation under the project TRAMs (Transactions and Active Database ....

....is proposed that aims at identifying and removing interferences between concurrent workflows, but without discussing event based process interaction, exception handling, or recovery. Contrary to what might be expected, the work done in the context of active database management systems (ADBMS) [13, 16] does not apply directly to what we discuss in this paper, although the ideas proposed could be implemented on top of an ADBMS. ADBMS allow to define events as part of the event condition action (ECA) rule paradigm: Upon the occurrence of an event, which can (among others) be an operation executed ....

N. Paton, O. Diaz, M. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of active behaviour. In N.W.Paton and M.H.Williams, editors, 1st Int. Wkshp. on Rules In Database Systems. Springer-Verlag, 1994.

....database systems are a natural fit for manufacturing applications. However, various active database systems have been developed to provide different sets of capabilities. Several dimensions can be used to characterize the capabilities and behavior of different active databases as discussed in [Pat93]. These dimensions relate to the structure, execution model and management of active rules. We note that some of the important points for providing multi step control are the following: Allowable sources for the events must include external messages or method invocations, since this is how the ....

N. Paton, et. al., "Dimension of Active Behaviour," Proceedings of the 1st International Workshop on Rules in Database Systems, August 1993, 40-57.

....only one argument (the receiver) 3.2 DIMENSIONS OF RULE MODELING The addition of rules to passive OODBs adds various new dimensions which need to be taken into account in an active OODB model. A comprehensive survey of various dimensions in providing active database functionality is given in [Paton 93] Various systems use different choices for these dimensions resulting in very divergent rule models. Since many of these dimensions are mutually exclusive, we now (informally) state choices in the rule model that we will formalize in Section 4: Rules are defined externally to a class. Rule ....

N. Paton, et. al., "Dimensions Of Active Behaviour," Proc. of Rules in Database Systems, 1993, 4057.

....and the consumption policy. The former identifies which part of the system is monitored, the latter describes the type of reaction when one event is detected. Event Sources for this purpose are: structure, error, and external. This is a subset of a larger set of event sources identified in [14]. The structure events are DB operations, such as insertions and deletions. The coordination rules monitor each application s output on such events. The error event is monitored by the contingency rule. This error can also be part of an external system, e.g. an operating system. The external ....

Paton, N., O. Diaz, M.H. Williams, J. Campin, A. Dinn & A. Jaime,`Dimensions of Active Behaviour', Proceedings of the 1st International Workshop on "Rules in Database Systems".

....level to model a given situation, a rule based approach may be found more appropriate at the implementation level (cf. 4, 20] 2 What are ECA rules used for In this section, we analyze for which kinds of situations ECA rules have been proposed. Typical problems handled by ECA rules are (cf. [19]) 1. maintaining static integrity constraints 2. maintaining derived data and materialized views 3. maintaining transitional (i.e. dynamic) integrity constraints 4. database access authorization 5. work step ordering 6. representing permissions to act 7. representing obligations to act We use a ....

N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of active behaviour. In N.W. Paton and M.H. Williams, editors, Rules in Database Systems: Proceedings of the 1st International Workshop on Rules in Database Systems, pages 40--57. Springer, September 1993.

....inheritance and overriding. We will then identify and discuss the choices that we have selected for the active rule model used as a basis for this research. 4 Dimensions of Active Rule Models A comprehensive survey of various dimensions in providing active database functionality is given in Paton, et al. 1993). These dimensions include knowledge model (what can be said about the active rules in the system) execution model (how a set of rules is treated at run time) and rule management model (the facilities provided by the system for managing rules) For the purposes of rule inheritance and ....

Paton, N. et. al. (1993). Dimensions Of Active Behaviour. Proc. of the 1st International Workshop on Rules in Database Systems, 40-57.

....of subprocesses greatly decreases the degree of parallelism since progress in the top level process is not possible until the complete subprocess has finished. We have tried to solve this problem in WISE by means of interprocess communications based on event and rule based (ECA rules) mechanisms [15, 21, 7]. Our approach differs from standard ECA rule management practice in that we do not use an active database system or a distributed event engine as the underlying platform. We opt instead for an architecture in which interprocess communication is implemented as an additional module of the execution ....

N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. .Jaime. Dimensions of active behaviour. In Proc. 1st Int. Wshp. on Rules In Database Systems, pages 40--57. Springer-Verlag, 1994.

....some distinctive features of the active extension to ROCK ROLL; and section 8 presents some conclusions. 2 Related Work 2. 1 Active Database Systems Limited space prevents a comprehensive description of the characteristics of active database systems; for a classification and brief survey, see [21]. The distinguishing feature of an active database system is that it is able to respond automatically to situations that arise inside or outside the database itself. The active behaviour of a database is generally described using rules, which most commonly have three components, an event, a ....

....triggered. The condition of a triggered rule is subsequently evaluated, and if true, then the action of the rule is scheduled for execution. The structural and behavioural characteristics of active database systems can be classified according to a number of dimensions, as outlined informally in [21]. For the purposes of this paper we classify the aspects to be described into two areas: knowledge model and execution model. The knowledge model represents the syntactic view of active rules as seen by the rule programmer. This has three main facets: Event language: a notation in which the ....

[Article contains additional citation context not shown here]

N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of active behaviour. In N.W. Paton and M.H. Williams, editors, Proc. 1st Int. Workshop on Rules In Database Systems, pages 40--57. Springer-Verlag, 1994.

....to the database. When an event has occurred that is of relevance to the rule, the condition of the rule is evaluated to examine the context within which the event has taken place, and if true then the action of the rule is executed. Different aspects of support for ECA rules are presented in [32]. Active database systems, however, have much in common with production systems (which support condition action rules) and some active databases provide direct support for production rules [27, 25] For certain tasks which monitor the state of the database, such as integrity constraint checking ....

....3. In this example database, the size of the ff memories in TREAT reaches the size of the underlying database when only 10 rules are present. 5 Consequences and Requirements 5. 1 Coupling Modes An important design issue for ECA rule systems is the range of coupling modes which are supported [13, 32]. The coupling mode of a rule indicates when the TABLE 3 #Rules TREAT OPRA I OPRAR 05 0.11 0.13 0.10 10 0.12 0.13 0.10 15 0.13 0.13 0.10 20 0.13 0.13 0.10 condition of a rule is evaluated relative to the event, and when the action is executed relative to the condition. For example, in Starburst ....

N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of active behaviour. In N.W. Paton and M.H. Williams, editors, Proc. 1st Int. Workshop on Rules In Database Systems, pages 40--57. Springer-Verlag, 1994.

....of checking all application code in a general purpose programming language for constraint violations would be very expensive, and the amount of rechecking involved would make evolution of the constraint set impractical. A number of designs and implementations of active databases now exist: [33] contains a survey of them. They vary in several dimensions, such as underlying data model, temporal behaviour, expressiveness of the language for specifying events and the extent to which the database history is accessible. The subject of the specification presented here is the Starburst active ....

N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of active behaviour. In N.W. Paton and M.H. Williams, editors, Proc. 1st Int. Workshop on Rules In Database Systems, pages 40--57. Springer-Verlag, 1994.

....database systems, while sharing a range of basic notions and constructs, support widely differing languages and execution models. A preliminary, informal framework for the comparison of active database systems and applications, designed to highlight common ground and key differences, is given in [15]. However, no formal model has yet been developed that encompasses the range of facilities supported by different active database systems. Despite this, an increasing number of researchers have been working on the formal specification of different aspects of active database functionality, with a ....

....rule is added to the conflict set, which is the store of triggered rules accessed by the scheduler which selects rule actions for execution. The structural and behavioural characteristics of active database systems can be classified according to a number of dimensions, as outlined informally in [15]. For the purposes of this paper we classify the aspects to be described into three areas: knowledge model, execution model, and management model. The knowledge model represents the syntactic view of active rules as seen by the rule programmer. This has three main facets: Event language: a ....

N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of active behaviour. In N.W. Paton and M.H. Williams, editors, Proc. 1st Int. Workshop on Rules In Database Systems, pages 40--57. Springer-Verlag, 1994.

....some distinctive features of the active extension to ROCK ROLL; and section 8 presents some conclusions. 2 Related Work 2. 1 Active Database Systems Limited space prevents a comprehensive description of the characteristics of active database systems; for a classification and brief survey, see [21]. The distinguishing feature of an active database system is that it is able to respond automatically to situations that arise inside or outside the database itself. The active behaviour of a database is generally described using rules, which most commonly have three components, an event, a ....

....triggered. The condition of a triggered rule is subsequently evaluated, and if true, then the action of the rule is scheduled for execution. The structural and behavioural characteristics of active database systems can be classified according to a number of dimensions, as outlined informally in [21]. For the purposes of this paper we classify the aspects to be described into two areas: knowledge model and execution model. The knowledge model represents the syntactic view of active rules as seen by the rule programmer. This has three main facets: Event language: a notation in which the ....

N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of active behaviour. In N.W. Paton and M.H. Williams, editors, Proc. 1st Int. Workshop on Rules In Database Systems, pages 40--57. Springer-Verlag, 1994.

....for the execution of the action. The condition is normally expressed as a database query, and the action normally involves some update, the sending of messages to users, or the control of some external device. However, the facilities supported by different active database systems are very diverse [25], and it can be difficult to ascertain exactly how specific proposals differ, or the consequences of such diversity. This difficulty derives in part from the informal descriptions that are normally used to present active database systems in the literature, where functionality is often only ....

N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of active behaviour. In N.W. Paton and M.H. Williams, editors, Proc. 1st Int. Workshop on Rules In Database Systems, pages 40--57. Springer-Verlag, 1994.

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N. W. Paton, O. D'iaz, M. H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of Active Behaviour. In Paton and Williams [PW93], pp. 40--57.

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Paton (N.W.), Diaz (O.), Williams (M.W.), Campin (J.), Dinn (A.) et Jaime (A.). -- Dimensions of active behaviour. In : Proceedings of 1st Int. Workshop on Rules in Database Systems (RIDS'93), ed. par Paton (N.W.) et Williams (M.H.). pp. 40--57. -- Edinburgh, Scotland, September 1994.

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Paton N.W., Diaz O., Williams M., Campin J., Dinn A., and Jaime A: "Dimensions of Active Behaviour", in Rules in Database Systems, Norman W. Paton and M. Howard Williams (Eds), Springer-Verlag, 1993.

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N. Paton, O. Diaz, M. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of active behaviour. In N. Paton and M. Williams, editors, Rules in Database Systems. , Workshops in Computing, pages 40--57. Springer, September 1993.

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N. W. Paton, O.Diaz, M. H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of Active Behaviour. In N. W. Paton and M H. Williams, editors, Rules in Database Systems, Edinburgh 1993, pages 40--57, 1993.

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N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, A. Jaime, "Dimensions of active behaviour," in Rules in Database Systems, 1st International Workshop RIDS '93, pp. 40-57. Springer (1993).

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N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of active behaviour. In N.W.Paton and M.H.Williams, editors, Proc. 1st Int. Wshp. on Rules In Database Systems, pages 40--57. SpringerVerlag, 1994.

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N.W. Paton, O. Diaz, M.H. Williams, J. Campin, A. Dinn, and A. Jaime. Dimensions of Active Behaviour. In N. W. Paton and M H. Williams, editors, Rules in Database Systems, Edinburgh 1993, pages 40--57, 1993.

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