ruby-on-rails - 在 Rails 中设置 create_join_table 迁移选项

Question

我有一些问题。我是 RoR 的新手

我正在尝试使用 Rails 迁移创建连接表。这方面的文档在这里... http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-create_join_table

当我做...

rails g migration CreateJoinTableUserOffer users offers

...它创建以下迁移

class CreateJoinTableUserOffer < ActiveRecord::Migration
 def change
   create_join_table:users, :offers  do |t|
         t.index [:user_id, :offer_id]
         t.index [:offer_id, :user_id]
      end       
    end
   end

当我这样做的时候...

rake db:migrate 

它创造...

-- Table: offers_users

-- DROP TABLE offers_users;

CREATE TABLE offers_users
(
 user_id integer NOT NULL,
 offer_id integer NOT NULL
)
WITH (



OIDS=FALSE
);
ALTER TABLE offers_users
 OWNER TO sudeepkaushik;

-- Index: index_offers_users_on_offer_id_and_user_id

-- DROP INDEX index_offers_users_on_offer_id_and_user_id;

CREATE INDEX index_offers_users_on_offer_id_and_user_id
 ON offers_users
 USING btree
 (offer_id, user_id);

-- Index: index_offers_users_on_user_id_and_offer_id

-- DROP INDEX index_offers_users_on_user_id_and_offer_id;

CREATE INDEX index_offers_users_on_user_id_and_offer_id
 ON offers_users
 USING btree
 (user_id, offer_id);

What I want to do is that I first of all want the table name to be users_offers instead of offers_users, for this you can specify the :table_name in the create_join_table migration. I'm not able to get the syntax of setting this option correctly. Need help here!

2nd, I noticed that this migration doesn't create the foreign keys that I would expect with the Users and Offers tables. Need your comments here also. Do I need to manually create the foreign keys myself?

Answer 1

您可以使用 table_name 选项定义您的连接表名称。

create_join_table :users, :offers, table_name: :users_offers

还有一个用于设置列选项的选项，称为 column_options，但我只让它对索引起作用，对外键不起作用。

create_join_table :users, :offers, column_options: { index: true }

这将创建所需的索引，但它会忽略 foreign_key: true。所以你需要单独创建它们。

add_foreign_key :users_offers, :users
add_foreign_key :users_offers, :offers

在您的模型中，您需要像这样添加关系:

# user.rb
has_and_belongs_to_many :offers, join_table: :users_offers

和:

# offers.rb
has_and_belongs_to_many :users, join_table: :users_offers