Suppliers(Sid: integer, sname:string, city:string, street:string) Parts(pid:integer, pname:string, color:string) Catalog(sid:integer, pid:integer, cost:real) Consider the following relational query on the above database: SELECT S.sname FROM Suppliers S WHERE S.sid NOT IN (SELECT C.sid FROM Catalog C WHERE C.pid NOT IN (SELECT P.pid FROM Parts P WHERE P.color ‘blue’)) Assume that relations corresponding to the above schema are not empty. Which of the following is the correct interpretation of the above query? Correct Answer Find the names of all suppliers who have not supplied only blue parts The correct answer is "option 4". EXPLANATION: The above query will return the Name of all suppliers who will not supply blue parts, which means it can include non-blue parts & null values. Consider the following table: Name ID COLOR A 1 Blue B 2 Blue C 3 Blue D 4 Blue E 5 Red F 6 Red G 7 Red H 8 Red I 9 Null J 10 Null The QUERY "SELECT P.pid FROM Parts P WHERE P.color ‘blue’ " will give: NAME ID COLOR E 5 red F 6 Red G 7 Red H 8 Red I 9 Null J 10 Null The Query "SELECT C.sid FROM Catalog C WHERE C.pid NOT IN (SELECT P.pid FROM Parts P WHERE P.color ‘blue’)" will give : NAME ID COLOR A 1 Blue B 2 Blue C 3 Blue D 4 Blue The query " SELECT S.sname FROM Suppliers S WHERE S.sid NOT IN (SELECT C.sid FROM Catalog C WHERE C.pid NOT IN (SELECT P.pid FROM Parts P WHERE P.color ‘blue’)) " will give : NAME ID COLOR E 5 Red F 6 Red G 7 Red H 8 Red I 9 Null J 10 Null Option 1: FALSE The non-blue part does not include the Null values. Option 2: FALSE It will include both Null values and Blue parts. Option 3: FALSE It will include only Blue parts. Option 4: TRUE It will include non-blue parts and null values. Hence, The correct answer is "option 4".