公交车路线查询系统后台数据库设计--引入步行路线

公交车路线查询系统后台数据库设计系列文章

数据库下载 (该数据库已经输入了广州市350条公交车路线作为测试数据)

在《查询算法》和《关联地名和站点》两篇文章中，已经实现了通过地名或站点进行路线查询的算法，但是在现实中，从起点到终点不一定全程都是乘车，例如，有以下3条路线：

R1: S1->S2->S3->S4->S5

R2: S6->S7->S2->S8

R3: S8->S9->S10

假如现在要从站点S1到S7，如果用Inquiry查询路线，显然没有合适的乘车方案。但是S2和S7相距仅仅一个站的距离，可以用步行代替，因此可以先从S1乘坐R1到S2再步行到S7。

为了实现在乘车路线中插入步行路线，在数据库使用WalkRoute(StartStop, EndStop, Distance, Remark)(StartStop-起始站点,EndStop-目的站点,Distance-距离,Remark-备注)储存距离较近的两个站点。

加入表WalkRoute后，查询算法也要作相应的修改，其实WalkRoute和RouteT0很相似，因此只需把WalkRoute看成是特殊的直达线路即可，修改后的InqueryT1如下： 

/*
查询站点@StartStops到站点@EndStops之间的一次换乘乘车路线，多个站点用'/'分开，如：
exec InquiryT1 '站点1/站点2','站点3/站点4'
*/

CREATE proc InquiryT1(@StartStops varchar(32),@EndStops varchar(32))
as
begin
declare @ss_tab table(name varchar(32))
declare @es_tab table(name varchar(32))
insert @ss_tab select Value from dbo.SplitString(@StartStops,'/')
insert @es_tab select Value from dbo.SplitString(@EndStops,'/')
if(exists(select * from @ss_tab sst,@es_tab est where sst.name=est.name))
begin
raiserror ('起点集和终点集中含有相同的站点',16,1)
return
end

declare @stops table(name varchar(32))
insert @stops select name from @ss_tab
insert @stops select name from @es_tab

declare @result table(
StartStop varchar(32),
Route1 varchar(256),
TransStop varchar(32),
Route2 varchar(256),
EndStop varchar(32),
StopCount int
)
declare @count int
set @count=0

--查询"步行-乘车"路线
insert @result
select
sst.name as StartStop,
'从'+r1.StartStop+'步行到'+r1.EndStop as Route1,
r1.EndStop as TransStop,
r2.Route as Route2,
est.name as EndStop,
r2.StopCount as StopCount
from
@ss_tab sst,
@es_tab est,
(select * from WalkRoute where EndStop not in (select name from @stops)) r1,
RouteT0 r2
where
sst.name=r1.StartStop
and r1.EndStop=r2.StartStop
and r2.EndStop=est.name
order by r2.StopCount
set @count=@@rowcount

--查询"乘车-步行"路线
insert @result
select
sst.name as StartStop,
r1.Route as Route1,
r1.EndStop as TransStop,
'从'+r2.StartStop+'步行到'+r2.EndStop as Route2,
est.name as EndStop,
r1.StopCount as StopCount
from
@ss_tab sst,
@es_tab est,
RouteT0 r1,
(select * from WalkRoute where StartStop not in (select name from @stops)) r2
where
sst.name=r1.StartStop
and r1.EndStop=r2.StartStop
and r2.EndStop=est.name
order by r1.StopCount
set @count=@count+@@rowcount

if(@count=0)
begin
--查询"乘车-乘车"路线
insert @result
select
sst.name as StartStop,
r1.Route as Route1,
r1.EndStop as TransStop,
r2.Route as Route2,
est.name as EndStop,
r1.StopCount+r2.StopCount as StopCount
from
@ss_tab sst,
@es_tab est,
(select * from RouteT0 where EndStop not in (select name from @stops)) r1,
RouteT0 r2
where
sst.name=r1.StartStop
and r1.EndStop=r2.StartStop
and r2.EndStop=est.name
and r1.Route<>r2.Route
order by r1.StopCount+r2.StopCount
end

select
StartStop as 起始站点,
Route1 as 路线1,
TransStop as 中转站点,
Route2 as 路线2,
EndStop as 目的站点,
StopCount as 总站点数
from
@result
end