Question

考虑以下（简化）电路模型 MySQL的：

create table circuit (
  id int not null auto_increment primary key,
  name varchar(30) not null
);
create table device (
  id int not null auto_increment primary key,
  circuit_id int not null references circuit (id),
  chip varchar(30) not null,
  primary key (id)
);
create table pin (
  id int not null auto_increment primary key,
  device_id int not null references device (id),
  name varchar(10) not null unique,
  unique (device_id, name)
);
create table wire (
  circuit_id int not null references circuit (id),
  pin1_id int not null unique references pin (id),
  pin2_id int not null unique references pin (id),
  primary key (pin1_id, pin2_id)
);

作为一个例子，考虑两个（有点无意义）的电路电阻连接在一个环路中：

        RES
    +---/\/\/--+
    |   A   B  |
    |          |
    |   RES    |
    ----/\/\/--+
        B   A

使用我前面描述的数据库结构，这可能是表示为：

insert into circuit (name) values ('example');
set @c = last_insert_id();

insert into device (circuit_id, chip) values (@c, 'RES');
set @r1 = last_insert_id();
insert into pin (device_id, name) values (@r1, 'A');
set @a1 = last_insert_id();
insert into pin (device_id, name) values (@r1, 'B');
set @b1 = last_insert_id();

insert into device (circuit_id, chip) values (@c, 'RES');
set @r2 = last_insert_id();
insert into pin (device_id, name) values (@r2, 'A');
set @a2 = last_insert_id();
insert into pin (device_id, name) values (@r2, 'B');
set @b2 = last_insert_id();

insert into wire (circuit_id, pin1_id, pin2_id) values
  (@c, @b1, @a2), (@c, @b2, @a1);

我如何在Haskell中表示这种结构？它将不绑定到数据库 - SQL就是这样我可以精确定义我想要表示的结构。

Answer 1

您的pin表类似于图表的邻接列表，因此我使用图表库 - Data.Graph或Data.Graph.Inductive。

代表Haskell的电路

1 个答案: