职员信息表：
CREATE TABLE [employee](
[employee_id] [numeric](18, 0) IDENTITY(1,1) NOT NULL,
[employee_name] [nvarchar](50) NOT NULL,
[mailbox] [nvarchar](50) NOT NULL,
[password] [nvarchar](50) NOT NULL,
[sex] [int] not null,
CONSTRAINT [PK_employee] PRIMARY KEY([employee_id]))
历史表：
CREATE TABLE [employee_history](
[employee_id] [numeric](18, 0) IDENTITY(1,1) NOT NULL,
[employee_name] [nvarchar](50) NOT NULL,
[mailbox] [nvarchar](50) NOT NULL,
[password] [nvarchar](50) NOT NULL,
[sex] [int] not null,
[changedate] datetime,
）
每次职员表的修改操作将修改前的数据保存在历史表中，仅添加了一个修改时间列。
环境：Microsoft SQL Server 2005
------解决方案--------------------
触发器语句中使用了两种特殊的表：deleted 表和 inserted 表
Deleted 表用于存储 DELETE 和 UPDATE 语句所影响的行的复本。在执行 DELETE 或 UPDATE 语句时，行从触发器表中删除，并传输到 deleted 表中。Deleted 表和触发器表通常没有相同的行。
------解决方案--------------------
历史表employee_id也是自增的啊?
试试
create trigger tu_employee on employee
for update
as
insert into employee_history(employee_name,mailbox,password,sex,changedate)
select employee_name,mailbox,password,sex,getdate()
from deleted
------解决方案--------------------
CREATE TRIGGER tr1 ON employee FOR insert,update,delete AS
delete * from employee_history
insert into employee_history select * from employee