create or replace type ob_alphabets as object (alpha char(1));
create table alphabets of ob_alphabets;

create or replace type ob_tabalpha as table of ob_alphabets;

declare 
a ob_tabalpha = new ob_tabalpha(); 
cursor c1 is select * from alphabets; 
b c1%rowtype; 
i int := 0; 
begin 
for c in c1 loop 
a(i):= c; 
i:=i+1; 
end loop; 
for i in 1..26 
loop 
dbms_output.put_line(a(i)); 
end loop; 
end;

begin

a.extend(count of records)

a(1) := record