B employee hire dates must precede employee

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Unformatted text preview: badge numbers are unique. Some employees do not have a badge number. D. When employee salaries are updates, the new salary cannot be less than the old salary. E. Employees are uniquely identified by their employee IDs. Every employee has an employee ID. Answer: D Explanation: Answer D is correct. To enforce this type of restriction triggers need to be used, not declarative integrity constraints. Incorrect Answers: A: This business rule can be enforced by means of declarative integrity constraints. FOREIGN KEY constraint will help in this case. B: This business rule can be enforced by means of declarative integrity constraints. CHECK constraint will help in this case. C: This business rule can be enforced by means of declarative integrity constraints. UNIQUE constraint works in this case. E: This business rule can be enforced by means of declarative integrity constraints. PRIMARY KEY constraint enforces these restrictions. Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 431-433 Chapt...
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This document was uploaded on 03/08/2014.

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