text: use proxy_service
  
  create table country
  (
      country_id   smallint identity,
      country_name varchar(30)       not null default 'Unknown',
      country_code varchar(2)        not null default 'NA',
      created_at   datetimeoffset(2) not null default SYSDATETIMEOFFSET(),
      constraint country_pk primary key nonclustered (country_id),
      constraint country_code_ui unique (country_code)
  )
  
  insert into country (country_name, country_code)
  values (default, default)
  
  create table proxy
  (
      proxy_id   int identity      not null,
      proxy_addr varchar(30)       not null,
      country_id smallint          not null default 1,
      created_at datetimeoffset(2) not null default sysdatetimeoffset(),
      updated_at datetimeoffset(2) not null default sysdatetimeoffset(),
      deleted_at datetimeoffset(2) null,
      constraint proxy_pk primary key nonclustered (proxy_id),
      constraint proxy_ui unique (proxy_addr),
      constraint proxy_country_fk foreign key (country_id) references country on delete cascade
  )
  
  insert into proxy (proxy_addr, country_id, deleted_at) values ('0.0.0.0:80', 1, sysdatetimeoffset())
  
  create table proxy_user
  (
      user_id    smallint identity not null,
      user_name  varchar(30)       not null default 'checker',
      created_at datetimeoffset(2) not null default sysdatetimeoffset(),
      constraint proxy_user_pk primary key nonclustered (user_id)
  )
  
  insert into proxy_user (user_name)
  values (default)
  
  create table stat
  (
      created_at  datetimeoffset not null default sysdatetimeoffset(),
      proxy_id    int            not null,
      conn_time   int            not null,
      conn_status bit            not null default 0,
      user_id     smallint       not null default 1,
      constraint stat_pk primary key nonclustered (created_at),
      constraint stat_proxy_fk foreign key (proxy_id) references proxy on delete cascade,
      constraint stat_user_fk foreign key (user_id) references proxy_user on delete cascade,
  )