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Consider the two relations given below
Given that A is the primary key of R, D is the primary key of S and there is a referential integrity among S.A and R.A, discuss all integrity constraints which are violated.
(i) Primary key of R contains the ‘null' value and the value ‘a1' is duplicated, therefore it violates the entity integrity constraint within the relation R.
(ii) In primary key of S, the value ‘d1' is duplicated; therefore it violates the entity integrity constraint within the relation S.
(iii) The foreign key S.A contains the value ‘a2', that is not available in the parent key R.A, thus it violates the referential integrity constraint within the relation S.
What is the use of integrity constraints? Integrity constraints make sure that changes made to the database by authorized users do not result in a loss of data consistency. The
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