Oracle触发器 - 检查已有数据

Question

我想检查输入的时间，以确定是否在已存储的任何其他约会的2小时内。

我的表测试（ID，数量& testdate，时间戳）

我有检查，看看新的时间是否为2小时的时间内触发我指定

create or replace trigger "TEST_T1" 
BEFORE 
insert on "TEST" 
for each row 
when (new.testdate is not null) 
begin 
    if (:new.testdate BETWEEN (to_timestamp('12-AUG-12 02:00:00PM') - interval '120' minute) 
         AND (to_timestamp('12-AUG-12 02:00:00PM') + interval '120' minute)) 
    then raise_application_error(-20634, 'This time clashes with another event.'); 
    end if; 
end; 

是有可能取代这次我从数据库中列出的时间列表？

与米哈尔Powaga帮助 - 下面 - 我设法得到这种使用

create or replace trigger "TEST_T1" 
BEFORE 
insert on "TEST" 
for each row 
when (new.testdate is not null) 
begin 
    DECLARE l_exists INTEGER; 
    BEGIN 
     SELECT COUNT(*) INTO l_exists FROM test WHERE testdate BETWEEN :new.testdate - interval '120' minute AND :new.testdate + interval '120' minute AND ROWNUM = 1; 
     IF l_exists = 1 THEN raise_application_error(-20634, 'This time clashes with another event.'); 
     END IF; 
    END; 
END; 

Answer 1

create or replace trigger "TEST_T1" 
BEFORE 
insert on "TEST" 
for each row 
when (new.testdate is not null) 
begin 
    declare qty integer := 0; 
    begin 
     select count(*) into qty from test where testdate between (:new.testdate - 2/24) and (:new.testdate + 2/24) and rownum = 1; 
     if qty > 0 then 
      raise_application_error(-20634, 'This time clashes with another event.'); 
     end if; 
    end; 
end; 

PS工作。请注意，我不是Oracle开发人员，因此可能有错误，但我认为这是要走的路:-)