因为要返回表对象，无论后续用什么方法返回，都先要声明全局type；并且，字段变量类型要为object，不能为record：
create or replace type t_test as object(
EMPNO NUMBER(4),
ENAME VARCHAR2(10),
JOB VARCHAR2(9),
SAL NUMBER(7,2)
);
create or replace type t_test_table as table of t_test;
至于返回表对象的方法，目前发现三种：
1、用数组
create or replace function f_test_array(v_deptno in number default null)
return t_test_table
is
v_test t_test_table := t_test_table();
cursor cur is select empno, ename, job, sal from emp where deptno = v_deptno;
begin
for c in cur loop
v_test.extend();
v_test(v_test.count) := t_test(c.empno, c.ename, c.job, c.sal);
end loop;
return v_test;
end;
2、用pipe
create or replace function f_test_pipe(v_deptno in number default null)