如何在 Rails 4 中创建复合主键

Question

请帮我将此 PostgreSQL 表转换为 Rails 迁移文件和模型

CREATE DATABASE ip2location WITH ENCODING 'UTF8'; \c ip2location

CREATE TABLE ip2location_db1(
  ip_from integer(10) NOT NULL,
  ip_to integer(10) NOT NULL,
  country_code character(2) NOT NULL,
  country_name character varying(64) NOT NULL,
  CONSTRAINT ip2location_db1_pkey PRIMARY KEY (ip_from, ip_to)
);

• 我想创建 Rails 模型来检索数据吗

Answer 1

终于找到了可行的解决方案

 def change
  create_table :ip2_location_v4s, id: false do |t|
   t.integer :ip_from
   t.integer :ip_to
   t.string :country_code
   t.string :country_name
  end

  execute "ALTER TABLE ip2_location_v4s ADD PRIMARY KEY (ip_from, ip_to);"
end

这生成了我需要的 SQL 表

-- 表：ip2_location_v4s

-- 删除表 ip2_location_v4s;

CREATE TABLE ip2_location_v4s
(
 ip_from bigint NOT NULL,
 ip_to bigint NOT NULL,
 country_code character varying(2) NOT NULL,
 country_name character varying(64) NOT NULL,
 CONSTRAINT ip2_location_v4s_pkey PRIMARY KEY (ip_from, ip_to)
) 

感谢@mohammad-shahadat-hossain 抽出宝贵时间

Answer 2

用于迁移脚本

class Iplocation2 < ActiveRecord::Migration
 def change
  create_table :ip2location_db1, id: false do |t|
    t.integer :ip_from 
    t.integer :ip_to
    t.string :country_code
    t.string :country_name
    t.timestamps
  end
 end
end

对于模型

class ip2location < ActiveRecord::Base
  self.primary_keys = :ip_from,:ip_to
  validates :language_id, uniqueness: { scope: [:id] }
end