sql oracle PL/SQL 上的错误：语句被忽略

Question

此 SQL 代码给我错误“第 2 行错误：PL/SQL：语句被忽略”，我正在处理 SQL oracle 应用程序 Express / APEX：我尝试了我能想到的一切，但它每次都会给我带来不同的问题。

CREATE or replace TRIGGER remove_artista 
   instead of delete on V_ARTISTA
REFERENCING old AS orow
FOR EACH ROW
BEGIN
if exists(select * from Utilizadores where pessoaID = orow.pessoaID) then
        delete from Pessoas where pessoaID = orow.pessoaID;
ELSE
        delete from Artistas where pessoaID = orow.pessoaID;
        delete from Pessoas where pessoaID = orow.pessoaID;
end if;
END;

风景：

create or replace view v_artista as 
 select 
pessoaID, nome_p, sexo, data_nasc, nome_art, biografica
from Pessoas natural inner join Artistas;

编辑：修复了代码上的一个小拼写错误。

Answer 1

我从您的触发器收到的完整错误如下：

LINE/COL ERROR
-------- -----------------------------------------------------------------
2/1      PL/SQL: Statement ignored
2/4      PLS-00204: function or pseudo-column 'EXISTS' may be used inside
         a SQL statement only

本质上，问题在于你不能if exists(...)像你所做的那样说。甲骨文不让你这么做。

相反，尝试将表中匹配行的数量选择Utilizadores到局部变量中，然后在if语句中使用它：

CREATE or replace TRIGGER remove_artista 
   instead of delete on V_ARTISTA
REFERENCING old AS orow
FOR EACH ROW
DECLARE
  l_count       INTEGER;
BEGIN
  select count(*) 
    into l_count
    from Utilizadores
   where pessoaID = :orow.pessoaID;

  if l_count > 0 then
        delete from Pessoas where pessoaID = :orow.pessoaID;
  ELSE
        delete from Artistas where pessoaID = :orow.pessoaID;
        delete from Pessoas where pessoaID = :orow.pessoaID;
  end if;
END;

我还需要替换orow为:orow. 进行此更改后，您的触发器也为我编译了。