Consider the following table structures related to a university for the below…

Final answer: Only the UPDATE that multiplies SALARY for employees whose DEPTNO matches the DID of the 'SCIENCE' department is correct.

Why this works:

• The statement "UPDATE EMPLOYEE SET SALARY = SALARY*1.20 WHERE DEPTNO IN (SELECT DID FROM DEPARTMENT WHERE DNAME = 'SCIENCE');" is valid because DEPTNO is a foreign key referencing the department's DID. The subquery returns the DID(s) for departments named 'SCIENCE', and the UPDATE updates only employees in those departments.

Why the other statements are incorrect or invalid:

• A statement that uses "UPDATE TABLE EMPLOYEE SET SALARY = SALARY*1.20 WHERE DNAME = 'SCIENCE';" is invalid for two reasons: standard SQL uses "UPDATE EMPLOYEE ..." (not "UPDATE TABLE EMPLOYEE"), and DNAME is not a column in the EMPLOYEE table. To filter by department name you must either use a subquery on DID (as above) or join to the DEPARTMENT table in the UPDATE.

• A statement that uses "ALTER TABLE EMPLOYEE SET SALARY = SALARY*1.20 ..." is invalid because ALTER TABLE modifies schema (columns/constraints), not row values. In addition, selecting the wrong column in the subquery or misspelling 'SCIENCE' would prevent correct identification of the target department.

Correct examples to achieve the raise:

1. Using a subquery: UPDATE EMPLOYEE SET SALARY = SALARY * 1.20 WHERE DEPTNO IN (SELECT DID FROM DEPARTMENT WHERE DNAME = 'SCIENCE');

2. Using a join (database dialects that support UPDATE ... FROM): UPDATE EMPLOYEE e SET SALARY = SALARY * 1.20 FROM DEPARTMENT d WHERE e.DEPTNO = d.DID AND d.DNAME = 'SCIENCE';

Conclusion: Only the UPDATE that uses DEPTNO matched to DID for the 'SCIENCE' department is correct. The other statements contain syntax or semantic errors and will not produce the intended result.