这是我创建的表格。
USE my_guitar_shop;
DROP TABLE IF EXISTS Products_Audit;
CREATE TABLE Products_Audit (
audit_id INT PRIMARY KEY,
category_id INT REFERENCES categories(category_id),
product_code VARCHAR ( 10 ) NOT NULL UNIQUE ,
product_name VARCHAR ( 255 ) NOT NULL,
list_price INT NOT NULL,
discount_percent INT NOT NULL DEFAULT 0.00 ,
date_updated DATETIME NULL);
创建名为products_after_update的触发器。此更新后,此触发器应将有关产品的旧数据插入到Products_Audit表中。然后,使用适当的UPDATE语句测试此触发器。
这是我创建的触发器,但数据未显示在Products_Audit表中,它显示全部为null。
USE my_guitar_shop;
DROP TRIGGER IF EXISTS products_after_update;
DELIMITER $$
CREATE TRIGGER products_after_update
BEFORE UPDATE ON products
FOR EACH ROW
BEGIN
INSERT INTO products_audit (audit_id, product_id, category_id, product_code,
product_name, list_price, discount_percent, date_updated)
SELECT audit_id, products.product_id, products.category_id, products.product_code,
products.product_name,products.list_price, products.discount_percent, date_updated
FROM products JOIN products_audit
ON products_audit.audit_id = (SELECT audit_id FROM inserted);
END $$
DELIMITER ;
使用INSERT INTO进行编辑
USE my_guitar_shop;
DROP TRIGGER IF EXISTS products_after_update;
DELIMITER $$
CREATE TRIGGER products_after_update
BEFORE UPDATE ON products
FOR EACH ROW
BEGIN
INSERT INTO products_audit (audit_id, product_id, category_id,product_code,
product_name, list_price, discount_percent, date_updated)
VALUES (OLD.audit_id, OLD.product_id, OLD.category_id, OLD.product_code,
OLD.product_name, OLD.list_price, OLD.discount_percent, OLD.date_updated)
DELIMITER ;
答案 0 :(得分:0)
您的插入过于复杂。正如triggers上的mysql文档所说:
在UPDATE触发器中,您可以使用OLD.col_name来引用列 更新前的行和NEW.col_name引用列 更新后的行。
因此,请在插入中使用OLD.column_name
格式。另外,我会将audit_id
字段设置为自动递增,并将其从插入中删除:
INSERT INTO products_audit (product_id, category_id, product_code,
product_name, list_price, discount_percent, date_updated)
VALUES (OLD.product_id, OLD.category_id, OLD.product_code,
OLD.product_name, OLD.list_price, OLD.discount_percent, OLD.date_updated)
答案 1 :(得分:0)
这是我如何做的一个例子:
CREATE OR REPLACE EDITIONABLE TRIGGER E_TABLE_TRG
before insert or update or delete on e_table
for each row
declare
l_seq number;
begin
-- Get a unique sequence value to use as the primary key
select s_seq.nextval
into l_seq
from dual;
if inserting then
:new.date_opened := sysdate;
:new.last_txn_date := null;
:new.status := 'A';
end if;
if inserting then
insert into e_table_history
(
t_seq,
user_id,
date_opened,
last_txn_date,
status,
insert_update_delete,
insert_update_delete_date
)
values
(
l_seq,
:new.user_id,
:new.date_opened,
:new.last_txn_date,
:new.status,
'I',
sysdate
);
elsif updating then
insert into e_table_history
(
t_seq,
date_opened,
last_txn_date,
status,
insert_update_delete,
insert_update_delete_date
)
values
(
l_seq,
:new.date_opened,
:new.last_txn_date,
:new.status,
'U',
sysdate
);
else
insert into e_table_history
(
t_seq,
date_opened,
last_txn_date,
status,
insert_update_delete,
insert_update_delete_date
)
values
(
l_seq,
:old.date_opened,
:old.last_txn_date,
:old.status,
'D',
sysdate
);
end if;
end;
/
ALTER TRIGGER E_TABLE_TRG ENABLE;
/