E. N. Hanson and J. Widom. An overview of production rules in database systems. Technical Report RJ 9023 (80483), IBM Almaden Research Center, October 12, 1992.  Home/Search   Document Details and Download   Summary   Related Articles   Check

.... an arbitrary SQL subexpression in this case semantics is defined in terms of oracle function that incapsulates the semantics of SQL statements) Suggested approach for integration of relational databases and reasoning is in a way a compromise between classical models of active databases [3], where relational model is extended by forward inference triggers, and dedutive databases, that are rather first order logic representation of relational structures. Presented approach allows using existing RDBMS software for reasoning over data contained there by inheriting implicit database ....

Hanson N.H.,Widom J. An Overview of Production Rules in Database Systems. In the Knowledge Engineering Review, Vol.8, No.2, 1993. pp.121--143.

....does not specify any mechanisms for ensuring that sites act according to their stated policies. Thus mech1 anisms developed for Hippocratic databases may provide the basis for designing enforcement in P3P. Related work includes research on integrating production rules with database systems (see [15] for an overview) The dominant application of the database rule systems is to monitor events (mostly updates) and cause specified actions to be triggered if certain conditions are satisfied. P3P preferences expressed in APPEL also consist of a set of rules. However, the APPEL rules have little in ....

E. N. Hanson and J. Widom. An Overview of Production Rules in Database Systems. The Knowledge Engineering Review, 8(2):121--143, June 1993.

....on which a trigger has been defined, the DBMS must determine whether or not satisfies the trigger condition. If the trigger condition is satisfied the trigger action is executed. A number of predicate indexing techniques and testing network structures have been proposed in this context. See [12, 4] for an overview. These solutions have been the basis for developing a number of main memory algorithms to address the event matching problem in content based subscription systems. Event matching algorithms in content based subscription systems can be divided into two categories: Predicate ....

E. Hanson and J. Widom. An overview of production rules in database systems. The Knowledge Engineering Review, vol. 8 no. 2, June 1993.

....and later migrated to Xerox Advanced Information Technology Center. The HiPAC prototype is an extension of the PROBE DBMS [CN90] but does not implement the full functionality of the HiPAC model. References: MD89] RCBB89] Cha89] DBBC88] DBM88] HLM88] Secondary: Cha93] Day88] [HW93] PDW 93] VK93] ZB90] 2.9 Iris Iris was developed at the Hewlett Packard Laboratories in Palo Alto. Although Iris does not claim to be active, its capability to evaluate functionally defined attributes propose many solutions that are useful in an active database context as well. Data updates are monitor in order to ....

....object oriented features. Triggers in Postgres were developed to implement views, inheritance mechanisms, and integrity constraints. A commercial version called ILLUSTRA, is available since References: RS87] SHH87] SHP88] SHP89] SJGP90] SK91] SR86] SRH90] Secondary: Cha93] [HW93] PDW 93] VK93] ZB90] 2.11 Ode Ode was developed at AT T Bell Laboratories. It is primarily an object oriented DBMS with activity extensions. First publications emphasize constraint and trigger management. The Ode rule language is very powerful and includes facilities for temporal information. Finite automata are ....

[Article contains additional citation context not shown here]

E.N. Hanson and J. Widom. An overview of production rules in database systems. Technical Report Annotation: See [HW93].

....Database event User defined event Selection event Boolean event Periodical event Delay event Figure 1: Classification of events Analogously to events we differentiate elementary and complex conditions. An elementary condition is either a predicate or a query over the data in a database [11] as e.g. a comparison of an attribute value of an object and a constant (e.g. order state = 2 ) a comparison of attribute values of two objects (e.g. order total credit limit ) or . a set operation on data (e.g. customer related to order ) Complex conditions consist of several ....

Hanson, E.N., Widom, J., An Overview of Production Rules in Database Systems, Working Paper CIS-TR-92-031, University of Florida, 1992.

....results of a case study, and introduces a meta model and a repository system for business rules. Keywords: Business Rule, Repository, Dynamic modeling, Active Database, ECA 1 INTRODUCTION Active databases are an important issue in current database research (cf. StHH87] DaBM88] WiCL91] [HaWi93]; ChMi93] Gatz94] The introduction of database triggers in commercial database management systems (DBMS) such as Ingres, Oracle, or Sybase are first approaches to make this research available for the development of information systems (IS) According to this progress on the implementation ....

.... Systems design, implementation, Legend: Other activities Data access Figure 1: Systems analysis focusing on business rules 2. 2 The Structure of Business Rules Rules in active databases (cf. DaBM88] are structured according to the Event ConditionAction (ECA) paradigm (cf. TsKL90] [HaWi93]) Because one of our goals is to derive implementations of business rules in active components, it seems to be appropriate to structure page 3 business rules accordingly. As a result of several case studies to extract business rules from practically applied IS [KnHS94] we use ECAA rules ....

Hanson, E.N., Widom, J., An Overview of Production Rules in Database Systems, in: Knowledge Engineering Review 8 (1993) 2, pp. 121 - 143. page - 18 -

....and applicability. The integration of forward chaining rule evaluation with databases to form active databases is proving to be valuable for the expression of core database functions, complex consistency constraints, workflow applications and computer aided manufacturing (CAM) applications[8,5]. Applications of these concepts are not limited to data in a single database at a single location. This is clearly the case for cooperative databases when it is important that changes in the values in one database be reflected by changes in values in another. For example, a just in time inventory ....

....Databases Rules for active database systems comprise a three part form, known as event condition action (ECA) Depending on the system, the event and event qualifications may be simple or involve complex logical compositions. Table 1 enumerates the primitive events that systems have included [9,8]. The intent is upon an event, the condition is evaluated. If the condition expression evaluation generates records, the records serve as parameters to an action. Expert system languages have been limited to condition action rules. Every update to the underlying state of the system is implicitely ....

Hanson, E. and J. Widom, "An Overview of Production Rules in Database Systems." The Knowledge Engineering Review, 8(2), 1993.

....active database systems. Active databases extend conventional passive systems to automatically respond to particular situations arisen in the database. The main means for active functionality has been active rules, which are situation action rules, triggered when a situation arises in the database [26, 34]. There are actually two kinds of active rules, namely production rules and event conditionaction (ECA) rules. Production (or data driven) rules are condition action rules: FRQGLWLRQ 7 (1 DFWLRQ, describing data states that should be reached in order to fire, while ECA (or event driven) ....

Hanson, E N and Widom, J, An overview of production rules in database systems, The Knowledge Engineering Review 8(2) (1993) 121-143.

.... some kind of knowledge, usually expressed in the form of rules [41] Rule systems have been incorporated into database systems using various integration schemes [12, 39, 41, 43] There are two main streams in the research of rules in databases or knowledge bases: active and deductive databases [29, 43]. Active databases use low level rules which are situation action rules, triggered when a situation arises in the database, while deductive databases are composed from high level rules which declaratively describe data in terms of other data, without an exact description of how new data are ....

....with various optimizations, and section 8 presents some performance results. Finally, section 9 concludes this paper with a summary of the main points and a discussion of future work. 2. Rule Integration in Active Databases Several active database systems have appeared in the literature so far [10, 12, 14, 21, 22, 28, 29, 38, 44]. All of them incorporate the active rule facility which allows one to provide automatic execution of database operations in response to certain events and or conditions. There is a certain confusion about the term active rules ; some researchers [28, 29] denote by this term the production rules ....

[Article contains additional citation context not shown here]

E.N. Hanson and J. Widom, An overview of production rules in database systems, The Knowledge Engineering Review 8(2) (1993) 121-143.

....in such a way that the database system can respond to the state changes in database by automatically executing some actions. The production rule concept in Artificial Intelligence was modified for the active database context so that rules can respond to state changes caused by database operations [7]. Expert systems and ADBMSs are very much related in that they are both based on the concept of rules although their rule structures are different. Fuzzy concepts were integrated into expert systems and database systems [3] 8] 9] 10] 11] and it was previously shown that incorporation of ....

E. N. Hanson and J. Widom, "An Overview of Production Rules in Database Systems," Tech. Rep., University of Florida, Department of Computer and Information Sciences, October 1992.

....priorities between di erent goals. For example, in the robot re ghter example 1.3, negation as failure is used to give the goal of saving humans a higher priority than the goal of saving artifacts. Explicit priorities between rules is often used in production systems and active database systems [2, 16, 11] to in uence the way rules are executed. In such systems, whenever di erent rules can be triggered in a state, the rules which have higher priority are triggered rst. Clearly, the notion of priority that 4 negation as failure induces, is di erent from the one used in classical production and ....

E.N. Hanson and J. Widom. An overview of production rules in database systems. The Knowledge Engineering Review, 8(2):121-143, 1993.

....by many related research efforts; in the following we list some of the most important ones. One of the prime motivations for developing the Heraclitus paradigm is the importance of deltas in connection with the execution model, or semantics of rule application, in active database systems [WC95, HW92, Sto92] Indeed, as first indicated in [HJ91] and detailed in Section 6 below, conceptually viewing deltas as first class citizens provides a useful basis for specifying and clarifying a variety of different execution models for active database, including for example the Starburst Active Database ....

....in connection with several application areas, including constraint maintenance, heterogeneous database interoperation, and incremental update for materialized views. The book [WC95] presents detailed descriptions of several active database systems and some of their applications, and the articles [HW92, Sto92] provide useful surveys of the field. A major difficulty facing the field of active databases today concerns the choice of execution model, or semantics, for rule application. Each of the active database systems proposed in the literature has a different execution model, and some [CCCR ....

E. Hanson and J. Widom. An overview of production rules in database systems. Technical Report RJ 9023 (80483), IBM Almaden Research Center, October 12, 1992.

....being referred to indirectly. A better approach might be to use o#sets, which would also eliminate the redundancy of storing both the unparsed contents of a page in page and the parsed contents in other tag, att, and especially vcvalue. Access to up to date information Active database technology [15] could be used to update or invalidate pages in the database as they expire. We would also like to provide Squeal with direct access to a search engine s database, which would also minimize data transfer delays. 6.3.2 Further evaluation It would be desirable to evaluate many structure based ....

Eric N. Hanson and Jennifer Widom. An overview of production rules in database systems. The Knowledge Engineering Review, 8(2), June 1993. 126

....to capture a variety of constraints associated with BODs; not only those specified by OAG but also those defined by application systems are supported. The concept and use of ECAA rules for constraint specification and enforcement is adapted from some existing active database management systems [ACT96, HAN93] such as HiPAC [DAY88, BUC95] Ariel [HAN92] Alert [SCH91] Sentinel [CHA94a] POSTGRESS [STO91] ODE [GEH91, GEH96] Starburst [LOH91, WID90] and our own work on OSAM .KBMS [SU91, SU92, SU93, SU95, SU96a, SU96b, SHY96] In active systems, database operations or user defined operations can be ....

Hanson, E.N., and Widom, J., "An Overview of Production Rules in Database Systems", The Knowledge Engineering Review, Vol. 8, No. 2, 1993, pp.121-143.

....Ariel focuses on extensions to relational DBMS towards production rules. Production rule processing, especially condition evaluation, has to be efficient. The Ariel publications also discuss suitable data structures and indexes. References: Han89] HB91] Han92b] Han92a] Secondary: CHS92] HW93] PDW 93] VK93] 2.4 ATM ATM (Activity Transaction Model) is an activity started at DIGITAL in 1990. Based on (and extending) the HiPAC execution model it provides a framework to specify complex dependencies among transactions. ATM uses ECA rules to specify complex and parallel workflows. ....

....and later migrated to Xerox Advanced Information Technology Center. The HiPAC prototype is an extension of the PROBE DBMS [CN90] but does not implement the full functionality of the HiPAC model. References: MD89] RCBB89] Cha89] DBBC88] DBM88] HLM88] Secondary: Cha93] Day88] HW93] PDW 93] VK93] ZB90] 2.9 Iris Iris was developed at the Hewlett Packard Laboratories in Palo Alto. Although Iris does not claim to be active, its capability to evaluate functionally defined attributes propose many solutions that are useful in an active database context as well. Data ....

[Article contains additional citation context not shown here]

E.N. Hanson and J. Widom. An overview of production rules in database systems. The Knowledge Engineering Review, Vol.8(No.2), June 1993.

....of solutions to the view and derived data update problem [CHM92] and issues in heterogeneous databases [CW92] Active database technology will also play an important role in the development of mediators [Wie92] for supporting database interoperation. As discussed in Section 2 (see also [HJ91a, HW92, Sto92] each of the active database systems described in the literature uses a different semantics or execution model for rule application. The variety of alternatives found in active database systems highlights the fact that the knowledge represented in them stems from two distinct ....

E. N. Hanson and J. Widom. An overview of production rules in database systems. Technical Report RJ 9023 (80483), IBM Almaden Research Center, October 12, 1992.

....for the particular inter database relationships we wish to be able to support and evolve, there exist many constructs native to existing DBMSs that can be utilizized. For example, there has been much work done involving the addition of rules to database systems [CW92, S 95, SJGP90, HKBBS92, HW92] particularly in support of constraints [CW93, GJ91] and views [DH84, BLT86, GMS93, LMSS95, Mot87] Similarly, schema integration [BLN86, SM89] has been studied extensively. Once we have the ability to add a new type of database system to an alliance, much of the conversion that needs to be done ....

E. Hanson and J. Widom. An overview of production rules in database systems. Technical Report RJ 9023 (80483), IBM Almaden Research Center, October 12, 1992.

....the property. The analysis methods are presented in the context of the Starburst Rule System. 1 Introduction Rules in active database systems allow specification of data manipulation operations that are executed automatically whenever certain events occur or conditions are met [DHW94,DW92,HW93] Active database rules provide a general and powerful mechanism for many database features, including integrity constraint enforcement, derived data maintenance, triggers, alerters, authorization checking, and versioning. In addition, active database systems provide a convenient platform for ....

E.N. Hanson and J. Widom. An overview of production rules in database systems. The Knowledge Engineering Review, 8(2):121--143, June 1993.

....Figure 1: Architecture below. Previously devised algorithms for view maintenance can be found in [1, 3, 5] and we have built upon these in our solutions. The problem of monitoring individual databases to detect relevant changes is central to the area of active databases, as represented in, e.g. [7, 9, 12]. We are exploiting appropriate parts of this technology in the WHIPS project. 3 Architecture Figure 1 illustrates the basic architecture of our system. The bottom of the figure depicts the multiple information sources of interest. These sources could include imagery, video, and text data, along ....

E.N. Hanson and J. Widom. An overview of production rules in database systems. The Knowledge Engineering Review, 8(2):121--143, June 1993.

....In the past decade there has been a surge of interest in adding rule processing to database systems. Deductive database systems use logic rules to provide an expressive query facility [CGT90,Ull89] Active database systems use Event Condition Action rules to provide reactive behavior [HW93] In this paper we focus on what we refer to as expert database systems. An expert database system is a conventional database system extended with a facility for creating and automatically executing Condition Action rules. Expert database systems originated by coupling a rule processor for a ....

....to the database. The basic algorithm for rule processing is: repeat until no rule has a true condition: select a rule r with a true condition; execute r s action In this paper, we do not consider the effect of a conflict resolution policy for selecting among multiple rules with true conditions [HW93] However, as an extension to our framework we plan to incorporate conflict resolution using rule priorities; see Section 6. Note also that the granularity of rule processing invocation with respect to database modifications [HW93] is irrelevant here in the context of rule analysis. 2.3 ....

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E.N. Hanson and J. Widom. An overview of production rules in database systems. The Knowledge Engineering Review, 8(2):121--143, June 1993.

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E. N. Hanson and J. Widom. An overview of production rules in database systems. Technical Report RJ 9023 (80483), IBM Almaden Research Center, October 12, 1992.

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E.N. Hanson and J. Widom. An overview of production rules in database systems. Technical Report UF-CIS-TR-92-031, University of Florida, 1992. Annotation: See [HW93].

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E. N. Hanson and J. Widom. An overview of production rules in database systems. The Knowledge Engineering Review, Vol 8:2, 121-143, 1993.

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E.N.Hanson, J.Widom: 'An Overview of Production Rules in Database Systems', The Knowledge Engineering Review, Vol. 8, No. 2, 1993.

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E.N. Hanson and J. Widom. An overview of production rules in database systems. Technical Report UF-CIS-TR-92-031, University of Florida, 1992.

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