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Composite Event Specification in Active Databases: Model & Implementation

Composite Event Specification in Active Databases: Model & Implementation,Narain H. Gehani,H. V. Jagadish,Oded Shmueli

Composite Event Specification in Active Databases: Model & Implementation   (Citations: 285)
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Active database systems require facilities to specify triggers that fire when specified events occur. We propose a language for specifying composite events as eveti expressions, formed using event operators and events (primitive or composite). An event expression maps an event history to anothe-r event history that contains only the events at which the event expression is "satisfied" and at which the trigger should 6re. We present several examples illustrating how quite complex event specifications are possible using event expressions. In addition to the basic event operators, we also provide facilities that make it easier to specify composite events. "Pipes" allow users to isolate sub-histories of interest. "Correlation variables" allow users to ensure that different parts of an event expression are satisfied by the same event, thereby facilitating the coordination of sub-events within a composite event. We show how to efficiently implement event expressions using finite automata. Each event causes an automaton to change state. When an automaton reaches an accepting state, a composite event of interest is recognized, and the corresponding trigger fired. Events have attributes. For primitive events, these could be parameters of the activity that caused the event, selected parts of the database state, or functions computed therefrom. For composite events, attributes are derived from the attributes of the constituent primitive events. These attributes can be used in checking conditions, and in any actions triggered. Event expressions can specify values (or sets or ranges of values) for particular attributes, and can even require that some attributes be equal. The composite event specified by the expression does not occur unless the specified condition on attributes is satisfied.
Conference: Very Large Data Bases - VLDB , pp. 327-338, 1992
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    • ...These include ODE [22], Snoop [10], and others [31] for active databases and the Situation Manager Rule Language [2], a general purpose event language...

    Segev Wasserkruget al. Efficient Processing of Uncertain Events in Rule-Based Systems

    • ...However, most of the previous works on active database management systems [22], publish/subscribe management systems [16], and complex event processors [39] did not address this issue...
    • ...Over the past few decades, many individual active database management systems, such as HiPAC [15], Ode [22,23], Snoop [9], SAMOS [21], and NAOS [14], have been developed...
    • ...The algorithms based on automata [16,22,39] or petri nets [21] cannot avoid redundant predictions...

    Chung-Wen Choet al. On-line rule matching for event prediction

    • ...Some examples include: the COMPOSE language of the Ode active database [32, 33, 34], the composite event detection language of the SAMOS active database [30, 31], Snoop [17] and its successor SnoopIB [2, 3], GEM [53], SEL [76], CEDR [7], ruleCore [72, 57], the SASE Event Language [75], the Cayuga Event Language [20], the original event specification language of XChange [21, 13, 14], and the unnamed languages proposed in the following ...

    Michael Eckertet al. A CEP Babelfish: Languages for Complex Event Processing and Querying S...

    • ...Various event languages have been proposed [8, 16, 17, 21, 28]...

    Bruno Cadonnaet al. Sequenced event set pattern matching

    • ...Event processing has been studied extensively in the past (Gatziu and Dirtrich 1994; Gehani et al. 1992; Chakravarthy and Mishra 1994; Widom and Ceri 1996), in the context of active databases...

    Fusheng Wanget al. Temporal

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