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Define Assertions in SQL
a. An assertion is a predicate that is expressing a condition we wish the database to always satisfy.
b. Domain constraints, functional dependency and referential integrity are unique forms of assertion.
c. In which a constraint cannot be expressed in these forms, we use an assertion, for example
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By using the delete operation some consisting records can be deleted from a relation. To delete some definite records from the database a condition is also specified based on which
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