存储过程+ mysql问题

Question

我已经创建了一个存储过程来删除多个表中的数据。我的工作流程如下

我使用的是MySQL5.0，在linux上运行

表依赖关系如下

表C依赖于表B表B依赖于表A

我想删除表A中的一条记录，并删除表B和C中的所有相关记录

1-删除明细表中的所有数据(C) (使用存储过程sp_delete_from_C)

2-删除相关数据直接子表(B) (使用存储过程sp_delete_from_B)

3-删除主表(A) (带有存储过程sp_delete_from_A)

我编写了以下过程

CREATE PROCEDURE sp_A_rollback(IN aId INT UNSIGNED)
READS SQL DATA
BEGIN
DECLARE b_id INT DEFAULT 0;

DECLARE cur_1 CURSOR  FOR SELECT id FROM b where a_id=aId;

OPEN cur_1;
read_loop: LOOP
  FETCH cur_1 INTO a_id;
  CALL sp_delete_from_C(b_id);
END LOOP;
CLOSE cur_1;

CALL sp_delete_from_B(aId);
CALL sp_delete_from_A(aId);


END //

我的问题是，

如果我单独运行这些过程，它就能正常工作

但是如果你运行sp_A_rollback，它只执行'sp_delete_from_C‘

我不知道为什么它不给另外两个sps打电话。我是mysql存储过程的newbee。有人能帮帮我吗？

提前感谢

sameera

Answer 1

我不知道你为什么要使用游标--你所需要的就是下面这样的东西：

drop procedure if exists cascade_delete_tableA;
delimiter #

create procedure cascade_delete_tableA
(
in p_id int unsigned
)
begin

delete from tableC where a_id = p_id;
delete from tableB where a_id = p_id;
delete from tableA where id = p_id;

end#

delimiter ;

从包装在事务中的应用程序代码中调用存储过程。

编辑

您将需要使用连接来从tableC中删除行。这里有一个更全面的示例供您学习http://pastie.org/1435521。此外，您的游标循环没有读取到正确的变量，这就是为什么它不能以当前的形式工作。我仍然建议你检查以下内容。

-- TABLES

drop table if exists customers;
create table customers
(
cust_id smallint unsigned not null auto_increment primary key,
name varchar(255) not null
)
engine=innodb;

drop table if exists orders;
create table orders
(
order_id int unsigned not null auto_increment primary key,
cust_id smallint unsigned not null
)
engine=innodb;

drop table if exists order_items;
create table order_items
(
order_id int unsigned not null,
prod_id smallint unsigned not null,
primary key (order_id, prod_id)
)
engine=innodb;

-- STORED PROCS

drop procedure if exists cascade_delete_customer;
delimiter #

create procedure cascade_delete_customer
(
in p_cust_id smallint unsigned
)
begin

declare rows int unsigned default 0;

-- delete order items

delete oi from order_items oi 
 inner join orders o on o.order_id = oi.order_id and o.cust_id = p_cust_id;

set rows = row_count();

-- delete orders

delete from orders where cust_id = p_cust_id;

set rows = rows + row_count();

-- delete customer

delete from customers where cust_id = p_cust_id;

select rows + row_count() as rows;

end#

delimiter ;

-- TEST DATA

insert into customers (name) values ('c1'),('c2'),('c3'),('c4');

insert into orders (cust_id) values (1),(2),(3),(1),(1),(3),(2),(4);

insert into order_items (order_id, prod_id) values 
(1,1),(1,2),(1,3),
(2,5),
(3,2),(3,5),(3,8),
(4,1),(4,4),
(5,2),(5,7),
(6,4),(6,8),(6,9),
(7,5),
(8,3),(8,4),(8,5),(8,6);

-- TESTING

/*

select * from customers where cust_id = 1;

select * from orders where cust_id = 1;

select * from order_items oi 
 inner join orders o on oi.order_id = o.order_id and o.cust_id = 1;

call cascade_delete_customer(1);

*/