“跨库导数据”、“事故处理”、“创建索引”、“使用触发器”等常用操作

好久没写过博客了，梳理下基础知识，复习下。

--跨库导数据
declare @ID int
declare @DAYear char(4)
declare @DAMonth char(2)
declare @DADay char(2)
declare @DATime datetime
declare @DAHour char(2)
declare @TemQty decimal(18, 6)
declare @HumQty decimal(18, 6)
declare @Note nvarchar(50)
declare @Lable int

declare TemHumCursor cursor for select *
from openrowset('SQLOLEDB','192.168.250.66';'sa';'tjdx',newcems.dbo.TemHum)
where DATime >'2012-11-26 12:12:40.527' order by DATime desc

open TemHumCursor
fetch next from TemHumCursor into @ID,@DAYear,@DAMonth,@DADay,@DATime,@DAHour,@TemQty,@HumQty,@Note,@Lable
while @@fetch_status=0
begin
insert into TemHum (DAYear,DAMonth,DADay,DATime,DAHour,TemQty,HumQty,Note,Lable) values (@DAYear,@DAMonth,@DADay,@DATime,@DAHour,@TemQty,@HumQty,@Note,0)

fetch next from TemHumCursor into @ID,@DAYear,@DAMonth,@DADay,@DATime,@DAHour,@TemQty,@HumQty,@Note,@Lable
end

close TemHumCursor
deallocate TemHumCursor
set nocount on

select * from TemHum order by DATime desc

go

--字段值减一
update ResultList set mydatetime = cast(cast(mydatetime as int)-1 as varchar(50))

select * from ResultList

go

--事故处理

create table 自动转账机
(
卡号 varchar(19) primary key,
金额 money check(金额>=0)
)
insert into 自动转账机 values('6222023100051898533',120.00)
insert into 自动转账机 values('6222023100051898573',0.00)

go

create table 自动取款机
(
卡号 varchar(19) primary key,
金额 money check(金额>=100)
)

delete from 自动取款机

go

insert into 自动取款机 values('6222023100051898533',120.00)
insert into 自动取款机 values('6222023100051898573',110.00)

go

--转账 余额不足 数据回滚 转账失败
begin try
begin tran
update 自动转账机 set 金额 = 金额+500 where 卡号 = '6220203200051898533'
update 自动转账机 set 金额 = 金额-500 where 卡号 = '6220203200051898573'
commit tran --执行成功
end try
begin catch
rollback tran --余额不足 数据回滚
end catch

go

--取款 余额不足 数据回滚
begin try
begin tran
update 自动取款机 set 金额 = 金额-500 where 卡号 = '6220203200051898573'
commit tran --执行成功
end try
begin catch
rollback tran --余额不足 数据回滚
end catch

go

select * from 自动转账机
select * from 自动取款机

go

drop table 自动转账机
drop table 自动取款机

go

--建表
create table card1 (cardid int,remain float)
go
create procedure mypro1
@incount int,
@outcount int,
@amount float
as

begin
declare @total float
select @total=remain from card1 where cardid=@outcount

if @total>=@amount
begin
update card1
set remain=remain-@amount where cardid=@outcount
update card1
set remain=remain+@amount where cardid=@incount
end

end
go
insert card1 values(1,1000.0)
insert card1 values(2,500.0)
go

create table card2(cardid int,remain float)
go

create procedure mypro2
@outid int,
@inid int,
@money float
as
begin
declare @total float
select @total=remain from card2 where cardid=@outid
begin transaction t1--设回滚点
if @total>@money
begin

update card2
set remain=remain-@money where cardid=@outid

update card2
set remain=remain+@money where cardid=@inid
print'转账成功'
commit transaction t1--提交事务

end
else
begin
print '转账失败'
rollback transaction t1--回滚
end

end

go

insert card2 values(1,1000.0)
insert card2 values(2,1000.0)
go
exec mypro2 2,1,1689
go
select * from card2

go
--创建索引

create nonclustered(表示非聚集索引，索引的一种类型) index meterno_alertcode_index on tbl(meterno,alertcode)

索引的类型：
nonclustered--非聚集索引
clustered--聚集索引
unique--唯一索引

go

--触发器
inserted和deleted 是触发器中的临时表
inserted 存放的是插入的数据
deleted 存放的是删除数据

插入时inserted表中有数据，deleted 中无数据

更新时，inserted表存放的是更新后的数据，deleted保存的是更新前的数据

删除时，inserted表中无数据，deleted保存删除的数据

--创建触发器

ALTER TRIGGER [dbo].[EnergyDataSumByHourNForCOP]
ON [dbo].[EnergyDataSumByHourN]
for INSERT,DELETE,UPDATE
AS
BEGIN

END