Example 1:
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declare
begin
for emp_record in(select * from emp)
loop
dbms_output.put_line('Name: '||emp_record.ename||' Department ID: '||emp_record.ename);
end loop;
end;
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Example 2: 
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declare
begin
update emp set sal=sal*(1+0.2) where job='SALESMAN';
if sql%notfound then -- if the update statement does not affect any row of data, execute
dbms_output.put_line('No employee needs salary increase');
else--If the update statement affects at least one row of data, execute
dbms_output.put_line('Yes'||sql%rowcount||'The salary of employees is increased by 20%');
end if;
end;
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When executing SELECT , INSERT , DELETE and UPDATE statements in a PL/SQL block , Oracle allocates a context area ( Context Area ), a buffer, in memory. The cursor is a pointer to the area , or named a work area ( Work Area ), or a structured data type.