You have been given two tables,CUSTOMER and SALE.You want to check the referential integrity constraint: SALE.CustomerNumber must exist in CUSTOMER.CustomerNumber
You run the following SQL query:
SELECT CustomerNumber
FROM SALE
WHERE CustomerNumber NOT IN
(SELECT CustomerNumber
FROM SALE,CUSTOMER
WHERE SALE.CustomerNumber = CUSTOMER.CustomerNumber);
What is shown in the results of this query?
A)All values of CustomerNumber that match the constraint.
B)All values of CustomerNumber that violate the constraint.
C)All values of CustomerNumber where
SALE.CustomerNumber = CUSTOMER.CustomerNumber.
D)A and C
E)B and C

Question

Quizplus · Accepted Answer

The query is checking for all CustomerNumbers in the SALE table that do not exist in the CUSTOMER table. These are the values that violate the referential integrity constraint. Therefore, the results will show all values of CustomerNumber that violate the constraint (option B). Option A is incorrect as it suggests that the query will show all values that match the constraint, which is not the case. Option C is also incorrect as it suggests that the query will show all values where SALE.CustomerNumber = CUSTOMER.CustomerNumber, which is not the same as checking for existence of SALE.CustomerNumber in CUSTOMER.CustomerNumber. Option D and E are incorrect as they include incorrect options.

You Have Been Given Two Tables,CUSTOMER and SALE