Rails 4迁移：has_and_belongs_to_many表名 [英] Rails 4 Migration: has_and_belongs_to_many table name

问题描述

我目前尝试将Rails 3.2应用程序切换到Rails 4.0。但是我有一个 has_and_belongs_many 模型的问题。

I currently try to switch a rails 3.2 app to rails 4.0. But I have one problem with a has_and_belongs_many model.

我创建了一个测试应用程序，但我遇到了同样的问题那里。这就是我所做的：

I have created a test app and I have the same problem there. This is what I have done:

创建了两个模型：foo_clip和foo_url

Created two models: foo_clip and foo_url

class FooClip < ActiveRecord::Base
  has_and_belongs_to_many :foo_urls

  attr_accessible :id, :name
end


class FooUrl < ActiveRecord::Base
  has_and_belongs_to_many :foo_clips

  attr_accessible :url
end

此后，我更新了迁移文件：

After this I have updated the migration files:

class CreateFooClips < ActiveRecord::Migration
  def change
    create_table :foo_clips do |t|
      t.string :name
      t.timestamps
    end
  end
end

class CreateFooUrls < ActiveRecord::Migration
  def change
    create_table :foo_urls do |t|
      t.string :url
      t.timestamps
    end
  end
end

现在我已经为has_and_belongs_to_many表创建了迁移文件

Now I have created the migration file for the has_and_belongs_to_many table

class CreateFooClipsFooUrls < ActiveRecord::Migration
  def change
    create_table :foo_clips_foo_urls do |t|
      t.belongs_to :foo_url
      t.belongs_to :foo_clip
    end
  end
end

在最后一步中，我创建了一个种子文件进行测试：

As last step I created a seed file for testing:

foourl1 = FooUrl.create!(:url => 'http://www.google.com')
foourl2 = FooUrl.create!(:url => 'http://www.apple.com')

fooclip1 = FooClip.create!(:name => 'TestClip1')

fooclip1.foo_urls << foourl1
fooclip1.foo_urls << foourl2

fooclip1.save

现在我做了：

rake db:drop
rake db:create
rake db:migrate
rake db:seed

并收到此错误：

PG::UndefinedTable: ERROR:  relation "foo_clips_urls" does not exist
LINE 5:         WHERE a.attrelid = '"foo_clips_urls"'::regcla...
                                          ^
:               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
               pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
                FROM pg_attribute a LEFT JOIN pg_attrdef d
                  ON a.attrelid = d.adrelid AND a.attnum = d.adnum
               WHERE a.attrelid = '"foo_clips_urls"'::regclass
                 AND a.attnum > 0 AND NOT a.attisdropped
               ORDER BY a.attnum

的顺序该表的postgres数据库称为：foo_clips_foo_urls

If I take a look at the postgres database the table is called: foo_clips_foo_urls

为什么会发生这种情况？

Any ideas why this happens?

推荐答案

我通过在每个模型中添加join_table名称来解决此问题，例如：

I fixed the problem by adding the join_table name to every model like:

has_and_belongs_to_many :foo_urls,  :join_table => :foo_clips_foo_urls

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