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Rules in active databases and integrity constraints

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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