选择每隔几天选择一次公交路线

Question

我正在研究公交车票预订系统。 在此，我为所有路线制作了表格，并在表格中添加了bus_number，fare等字段。 现在，我们的公交车每隔一天便会反方向行驶一次，即，如果公交车在2011年12月21日从X-> Y出发，则同一辆公交车将在下一个日期行驶Y-> X。 那么如何获得公共汽车的方向呢？ 如果我为每个巴士服务提供商创建表格并添加巴士号码，然后在日期中添加一个类似于“ to”的标识符，我认为可以知道接下来几天的状态。 我不知道这是个好主意，所以请帮助我。

Answer 1

如果不知道现有表的确切细节，则很难提供确定的解决方案。 无论如何，这是关于如何固定公共汽车及其站点和票价的建议：

CREATE TABLE `bus` (
  `id` int unsigned not null primary key auto_increment,
  `bus_number` varchar(55) not null,
   UNIQUE KEY `busUidx1` (`bus_number`)
) ENGINE=InnoDB;

CREATE TABLE `bus_stop` (
  `id` int unsigned not null primary key auto_increment,
  `stop_description` varchar(250) not null,
  UNIQUE KEY `bus_stopUidx1` (`stop_description`)
) ENGINE=InnoDB;

CREATE TABLE `bus_route` (
  `id` int unsigned not null primary key auto_increment,
  `bus_id` int unsigned not null,
  `route_date` date not null,
  `bus_start_stop_id` int unsigned not null,
  `bus_end_stop_id` int unsigned not null,
  `fare` decimal (10,2) not null,
   UNIQUE KEY `bus_stopUidx1` (`bus_id`,`route_date`),
CONSTRAINT `fk_bus_route_bus_fk1` FOREIGN KEY (`bus_id`) REFERENCES `bus` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `fk_bus_route_stop_fk1` FOREIGN KEY (`bus_start_stop_id`) REFERENCES `bus_stop` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `fk_bus_route_stop_fk2` FOREIGN KEY (`bus_end_stop_id`) REFERENCES `bus_stop` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB;

使用这种模型，您应该能够存储公交车的列表（在bus表中），所有可能的站点的清单（在bus_stop表中）以及给定日期的公交路线。 它还将使您可以灵活地打破“从X> Y出发的巴士，然后总是从Y> X出发的巴士”的规则，如果我过去乘坐的公共汽车可以通过，那么可能会有用;-)

编辑

因此，这里有一些示例数据试图进一步说明我的答案：

insert into bus (bus_number) values ('Red Bus 1');
insert into bus (bus_number) values ('Red Bus 2');
insert into bus (bus_number) values ('Yellow Bus 1');
insert into bus (bus_number) values ('Yellow Bus 2');

insert into bus_stop (stop_description) values ('Stop 1');
insert into bus_stop (stop_description) values ('Stop 2');
insert into bus_stop (stop_description) values ('Stop 3');
insert into bus_stop (stop_description) values ('Stop 4');

insert into bus_route (bus_id,route_date,bus_start_stop_id,bus_end_stop_id,fare)
values (
(select id from bus where bus_number = 'Red Bus 1'),
'2011-12-11',
(select id from bus_stop where stop_description = 'Stop 1'),
(select id from bus_stop where stop_description = 'Stop 2'),
3.45);

insert into bus_route (bus_id,route_date,bus_start_stop_id,bus_end_stop_id,fare)
values (
(select id from bus where bus_number = 'Red Bus 1'),
'2011-12-12',
(select id from bus_stop where stop_description = 'Stop 2'),
(select id from bus_stop where stop_description = 'Stop 1'),
3.45);

insert into bus_route (bus_id,route_date,bus_start_stop_id,bus_end_stop_id,fare)
values (
(select id from bus where bus_number = 'Yellow Bus 1'),
'2011-12-11',
(select id from bus_stop where stop_description = 'Stop 3'),
(select id from bus_stop where stop_description = 'Stop 4'),
1.95);

insert into bus_route (bus_id,route_date,bus_start_stop_id,bus_end_stop_id,fare)
values (
(select id from bus where bus_number = 'Yellow Bus 1'),
'2011-12-12',
(select id from bus_stop where stop_description = 'Stop 4'),
(select id from bus_stop where stop_description = 'Stop 3'),
1.95);

最后是将表连接在一起的查询：

select b.bus_number,
       br.route_date,
       bs.stop_description as start,
       be.stop_description as end,
       br.fare
from bus_route br
inner join bus b on b.id = br.bus_id
inner join bus_stop bs on bs.id = br.bus_start_stop_id
inner join bus_stop be on be.id = br.bus_end_stop_id;