Consider the relation shown in Figure 24.2 (d). How would it appear to a user with classification U? Suppose a classification U user tries to update the salary of "Smith" to $50,000; what would be the result of this action?
What will be an ideal response?
EMPLOYEE would appear to users within classification U as follows:
NAME SALARY JobPerformance TC
Smith U null U null U U
If a classification U user tried to update the salary of Smith to $50,000, a third
polyinstantiation of Smith's tuple would result as follows:
NAME SALARY JobPerformance TC
Smith U 40000 C Fair S S
Smith U 40000 C Excellent C C
Smith U 50000 U null U U
Brown C 80000 S Good C S
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