外键在轨道4 [英] Foreign key in rails 4

问题描述

我正在使用Rails 4和SQLite。我试图添加外键到我的指标表。请参阅下面的代码

  class指标< ActiveRecord :: Base 
 belongs_to：objetive 
 belongs_to：responsible，class_name：Person
 
 end 
  

迁移脚本：

  class AddFksToIndicator< ActiveRecord :: Migration 
 def change 
 add_reference：indicators，：objective，index：true 
 add_reference：indicators，：responsible，index：true 
 end 
 end 
  

运行迁移一切正常，所以我在控制台中试过：

  2.0.0p247：002> i = Indicator.new 
 => ＃<指标id：nil，name：nil，created_at：nil，updated_at：nil，objective_id：nil，responsible_id：nil> 
 2.0.0p247：002> i.objective_id = 0 
 2.0.0p247：003> i.save 
  

令我惊讶的是，指标已经被保存了，没有 obective 与id = 0。

最后，我检查了指标表架构和我得到：

  CREATE TABLEindicators（idINTEGER PRIMARY KEY AUTOINCREMENT NOT NULL，namevarchar（255），created_atdatetime，updated_atdatetime，objective_id integer，responsible_idinteger）; 
 CREATE INDEXindex_indicators_on_objective_idON指标（objective_id）; 
 CREATE INDEXindex_indicators_on_responsible_idON指标（responsible_id）; 
  

为什么在 objective_id 和 responsible_id ？
我做错了什么？

解决方案根据 Ruby on Rails 4.2发行说明，只有mysql，mysql2和postgresql适配器支持外键。

不幸的是，sqlite3适配器没有。

I'm using Rails 4 and SQLite. I'm trying to add foreing keys to my indicators table. Please see my code below

class Indicator < ActiveRecord::Base
  belongs_to :objetive
  belongs_to :responsible, class_name: "Person"

end

The migration script:

class AddFksToIndicator < ActiveRecord::Migration
  def change
      add_reference :indicators, :objective, index: true
      add_reference :indicators, :responsible, index: true
  end
end

when run the migration all is ok, so I tried in console:

2.0.0p247 :002 > i = Indicator.new
 => #<Indicator id: nil, name: nil, created_at: nil, updated_at: nil, objective_id: nil, responsible_id: nil> 
2.0.0p247 :002 > i.objective_id = 0
2.0.0p247 :003 > i.save

To my surprise, the indicator was saved and there is no obective with id = 0.

Finally, I checked the indicators table schema and I get:

CREATE TABLE "indicators" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "name" varchar(255), "created_at" datetime, "updated_at" datetime, "objective_id" integer, "responsible_id" integer);
CREATE INDEX "index_indicators_on_objective_id" ON "indicators" ("objective_id");
CREATE INDEX "index_indicators_on_responsible_id" ON "indicators" ("responsible_id");

Why there is no foreign key constraint on objective_id and responsible_id? Am I doing something wrong?

解决方案

According to Ruby on Rails 4.2 Release notes, only the mysql, mysql2 and postgresql adapters support foreign keys.

Unfortunately, the sqlite3 adapter does not.

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