[英]Trigger with lookup from another table
我正在學習專門針對PL / SQL的觸發器,並且我想學習如何使用觸發器在多個表上進行操作,但是在理解過程時遇到了麻煩。 這是一個例子:
CREATE TABLE Sess
(code INTEGER NOT NULL,
dateStart DATE NOT NULL,
dateEnd DATE NOT NULL,
CONSTRAINT KeySess PRIMARY KEY(code)
)
CREATE TABLE Ins
(codeIns CHAR(12) NOT NULL,
code INTEGER NOT NULL,
dateIns DATE NOT NULL,
dateAb DATE,
note INTEGER,
CONSTRAINT KeyIns PRIMARY KEY (codeIns, code)
)
1 /我正在嘗試建立一個可以確保這一點的觸發器:
before Insert or Update Ins
dateAb is between dateStart and dateEnd
2 /我也想ALTER TABLE
並鎖定Ins中的代碼和codeIns,因此沒有人可以更新它們,但我不知道該命令。
對於第一個觸發器,我嘗試了類似的方法:
CREATE OR REPLACE TRIGGER test
BEFORE INSERT OR UPDATE OF dateAb ON Ins
FOR EACH ROW
DECLARE
start date;
BEGIN
SELECT DISTINCT s.dateStart INTO start
WHERE Ins.code = s.code
IF (:NEW.dateAb < start) THEN
raise_application_error(-20101,'dateAb incorrect');
END IF;
END;
注意:我沒有聲明變量end來檢查它是否在中間,我的目的是測試正確的語法
注2:表為空。
我有Warning: Trigger created with compilation errors.
和3個錯誤:
PL/SQL: SQL Statement ignored
4/40 PL/SQL: ORA-00923: key-word FROM absent
9/5 PLS-00103: Encountered the symbol "IF" when expecting one of the
following:
;
最后,就像我說的那樣,我不知道正確的語法來鎖定表上的列以防止更新或可能的話。
我正在學習,所以如果你們中的一個可以教我正確地處理我的兩個請求的方法,我將不勝感激。 謝謝
嘗試這個:
create or replace trigger test
before insert or update of dateab on ins
for each row
declare
l_sess_start date;
begin
select s.datestart into l_sess_start
from sess s
where s.code = :new.code;
if :new.dateab < l_sess_start then
raise_application_error
( -20101
, 'Start date ' || to_char(:new.dateab,'DD-MON-YYYY') ||
' cannot be before ' || to_char(l_sess_start,'DD-MON-YYYY'));
end if;
end;
測試:
insert into sess values (1, date '2018-04-22', date '2018-04-30');
insert into ins values ('Z', 1, date '2018-04-01', date '2018-04-01', null);
ERROR at line 1:
ORA-20101: Start date 01-APR-2018 cannot be before 22-APR-2018
ORA-06512: at "WILLIAM.TEST", line 10
ORA-04088: error during execution of trigger 'WILLIAM.TEST'
PLS-00103: Encountered the symbol "IF" when expecting one of the
following:
;
此錯誤是因為您不見了;
選擇語句后
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.