Question

我正在尝试使用establish_connection迁移到Rails中的单独数据库。我在迁移文件中有类似的内容：

def change
  ActiveRecord::Base.establish_connection("user_#{Rails.env}")
  ActiveRecord::Base.initialize_schema_migrations_table

  create_table "users", :force => true do |t|
    t.string   "email",  
end

在yml中我有这个配置：

user_development:
  adapter: postgresql
  encoding: unicode
  database: MyApp_user_development
  pool: 5
  host: localhost
  username: xxx
  password: xxx

我也定义了这样的用户模型：

class User < ActiveRecord::Base
  establish_connection "user_#{Rails.env}"
  [...]
end

现在，数据库已存在，但在运行rake db:migrate时出现此错误：

==  CreateUserOnSeparateDb: migrating =========================================
rake aborted!
An error has occurred, this and all later migrations canceled:

connection is closed

你们有谁知道发生了什么事？

我还尝试将establish_connection调用移动到迁移文件中的connection方法。在这种情况下，表是在迁移时创建的，但后来我得到了相同的错误（因此以某种方式在其他迁移中失败），并且它没有创建schema_migrations表...

任何帮助？

Answer 1

按照以下步骤解决了上述问题。

class AddCustomTbl < ActiveRecord::Migration

  def connection
    ActiveRecord::Base.establish_connection(Rails.env).connection
  end

  def up
    # Connection with user_#{Rails.env}
    oldEnv = Rails.env
    Rails.env = "user_#{Rails.env}"
    ActiveRecord::Base.establish_connection(Rails.env)
    create_table "users", :force => true do |t|
      t.string   "email"
    end
    # Connection with Rails.env
    Rails.env = oldEnv
    ActiveRecord::Base.establish_connection ActiveRecord::Base.configurations[Rails.env]
  end

  def down
    # Connection with user_#{Rails.env}
    oldEnv = Rails.env
    Rails.env = "user_#{Rails.env}"
    ActiveRecord::Base.establish_connection(Rails.env).connection
    drop_table :users
    # Connection with Rails.env
    Rails.env = oldEnv
    ActiveRecord::Base.establish_connection ActiveRecord::Base.configurations[Rails.env]
  end
end

Rails将DB迁移分开工作

1 个答案: