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Rules in active databases and integrity constraints

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Rules in active databases and integrity constraints. Recap integrity constraints. normal forms express FDs, MVDs, JDs candidate and foreign keys entity integrity referential integrity; foreign key rules business (enterprise) integrity constraint rules domain constraints

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Rules in active databases and integrity constraints

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  1. Rules in active databases and integrity constraints

  2. Recap integrity constraints • normal forms • express FDs, MVDs, JDs • candidate and foreign keys • entity integrity • referential integrity; foreign key rules • business (enterprise) integrity constraint rules • domain constraints • attribute constraints • relation constraints • database constraints

  3. Integrity constraints - issues • declarative • do not specify when to be applied and what action to take in case of violation, because they are known by default • application • NF, attribute and relation constraints and CK - instantaneously • database constraints and FK - deferred until end of transaction • action • relation constraints and CK - reject • database constraints - ROLLBACK transaction • FK - FK rules

  4. Examples • provide examples of integrity constraints and consider the two issues • application • reaction to violation

  5. Recap rules in active databases • general model • event • condition • action • in the rest of this lecture rules are considered only from the point of view of enforcing integrity constraints

  6. Rules in active databases - issues • procedural • specify when to be checked • what event (UPDATE, DELETE, INSERT) • on which object • specify the action to be taken

  7. Activity • (possible topic for the last coursework) • compare, from the point of view of integrity constraint enforcement: • normal forms • keys (candidate and foreign) • domain, attribute, relation and database constraints (conditional expressions written explicitly) • rules (from active databases)

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