小编Chi*_*bak的帖子

我试图创建一个触发器:

create trigger afterupdate 
after insert on friends
for each row 


begin 
dbms_output.put_line('hello world');
end afterupdate;

但是出现以下错误:

"cannot create triggers on objects owned by SYS"

我正在尝试重命名w3schools 网站中的列名称

ALTER TABLE customers
  RENAME COLUMN contactname to new_name;

但是，上面的代码会引发语法错误。我究竟做错了什么？

我在从游标中获取值到变量时遇到问题:

create or replace 
procedure projectinfo(num clubs.clubid%type) 
as
--identify variables
p_cln clubs.clubname%type;
p_projn projects.projectname%type;
p_projnum number;
p_taskn tasks.taskname%type;
p_tasknum number;

cursor cur is 
select c.clubname, p.projectname, t.taskname 
from clubs c join projects p on  c.clubid=p.clubid
join tasks t on t.projectid=p.projectid
where c.clubid=num;
--I have checked the above cursor and it's worked fine!!!
begin
p_projnum:=0;
p_tasknum:=0;

open cur;

loop

fetch cur into p_cln,p_projn, p_taskn;
dbms_output.put_line(p_cln|| ' ' ||p_projn|| ' ' || p_taskn);
-- the above command does not print variable values!!! …