Lab 18.3 Exercises

18.3.1 Use Multilevel Collections

In this exercise, you will learn more about multilevel collections.

Create the following PL/SQL script:

 -- ch18_4a.sql, version 1.0 SET SERVEROUTPUT ON DECLARE    TYPE table_type1 IS TABLE OF integer INDEX BY BINARY_INTEGER;    TYPE table_type2 IS TABLE OF table_type1 INDEX BY BINARY_INTEGER;    table_tab1 table_type1;    table_tab2 table_type2; BEGIN    FOR i IN 1..2 LOOP       FOR j IN 1..3 LOOP          IF i = 1 THEN             table_tab1(j) := j;          ELSE             table_tab1(j) := 4 - j;          END IF;          table_tab2(i)(j) := table_tab1(j);          DBMS_OUTPUT.PUT_LINE ('table_tab2('i')('j'): 'table_tab2(i)(j));       END LOOP;    END LOOP; END; 

Execute the script, and then answer the following questions:

a)	Execute the script ch18_4a.sql and explain the output produced.
b)	Modify the script so that instead of using multilevel index-by tables it uses a nested table of index-by tables.
c)	Modify the script so that instead of using multilevel index-by tables it uses a nested table of varrays.