I need answer for questions 3 and 4 please help ( database )

1. Execute the command set serveroutput on; What does this command do? Google it on the Internet. 2. Type the following program and execute it. Can you tell from the result what the command DBMS_OUTPUT.PUT_LINE does? --PL/SQL program to display current date DECLARE today_date DATE; BEGIN today_date := SYSDATE; DBMS_OUTPUT.PUT_LINE('Today''s date is '); DBMS_OUTPUT.PUT_LINE(today_date); END; 3. Before you begin to work on the following questions, first download createDB.sql from the course website and execute it. Read the following program and figure out what it does. Then type it and execute it to verify if you are right. --PL/SQL program to get grade statistics DECLARE na integer :=0; BEGIN Select count(*) into na from gradeReport where grade='A'; if (na > 0) then DBMS_OUTPUT.PUT_LINE('there are total ' || na || ' A''s'); else DBMS_OUTPUT.PUT_LINE('No student makes an A'); end if; END; 4. Revise the above program, so that it will output the statistics for the grades A, B, C, D, and F.