DECLARE
n NUMBER := 10;
PROCEDURE do_something (
n1 IN NUMBER) IS
BEGIN
dbms_output.put_line(n1); -- prints 10
--n1:=20; --illegal assignment.
END;
BEGIN
do_something(n);
do_something(20);
END;
来源： https://yq.aliyun.com/ziliao/119492
原文：http://www.cnblogs.com/yldf/p/7736370.html