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)