routview.sql

铁路列车车辆监控系统本系统要求PC机有两个串行通讯串口

create view CityNum(城市号,城市名)
as
select * from
(
select 城市号,城市名 from MainCity
union
select 城市号,城市名 from 一般城市)derivedtbl

create view MainCity(城市号,城市名)
as
select 省会号+300,省会名 from 省会

create view NNRoutInfo(城城路段号,路段起点,路段终点)
as
select 路段号,b1.城市名,b2.城市名
from 铁路网 a,一般城市 b1,一般城市 b2
where b1.城市号=a.路段起点 and b2.城市号=a.路段终点

create view NMRoutInfo(城省路段号,路段起点,路段终点)
as
select 路段号,城市名,省会名
from 铁路网 a,一般城市 b,省会 c
where b.城市号=a.路段起点 and c.省会号+300=a.路段终点

create view MNRoutInfo(城省路段号,路段起点,路段终点)
as
select 路段号,省会名,城市名
from 铁路网 a,一般城市 b,省会 c
where  b.城市号=a.路段终点 and c.省会号+300=a.路段起点

create view MMRoutInfo(省省路段号,路段起点,路段终点)
as
select 路段号,b.省会名,c.省会名
from 铁路网 a,省会 b,省会 c
where b.省会号+300=a.路段起点 and c.省会号+300=a.路段终点

create view XMRoutInfo(路段号,路段起点,路段终点)
as
select *
from(
select *
from MMRoutInfo
union
select *
from NMRoutInfo)derivedtbl

create view NXRoutInfo(路段号,路段起点,路段终点)
as
select *
from(
select *
from NMRoutInfo
union
select *
from NNRoutInfo)derivedtbl

create view XNRoutInfo(路段号,路段起点,路段终点)
as
select *
from(
select *
from MNRoutInfo
union
select *
from NNRoutInfo)derivedtbl

create view MXRoutInfo(路段号,路段起点,路段终点)
as
select *
from(
select *
from MNRoutInfo
union
select *
from MMRoutInfo)derivedtbl