postgresql - postgreSQL 中的触发函数？

Question

我正在尝试制作一个触发器函数，该函数将检查在插入/更新事件日期记录时信息是否有效:

create or replace function trigf() returns trigger as $$
declare bad_date record;
begin
     select festival.title into bad_date
     from festival
     where new.title = festival.title and (new.edate < festival.sdate or new.edate > festival.edate);

     if exists bad_date then
                 raise notice 'Error: Event Date does not Correlate with the Festival.';
                if T = 'insert' then return null;
                    else return old;
                        end if;
         else
             return new;
         end if;
 end;
 $$language plpgsql;

 create trigger T
 before insert or update on event
 for each row
 execute procedure trigf();

编译顺利通过，但在尝试插入值时出现错误，指出 bad_date 不存在。

Answer 1

代替:

declare bad_date record;

if exists bad_date then

应该是:

declare bad_date text; -- or same type of festival.title 

if bad_date IS NOT NULL then