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在專案中連接另一個 Database

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有時候會需要連接另外一個 database 的資料，rails 可以很方便地來做連接!

在 model 底下建立子資料夾，連接到另外一個 database，不過關聯就需要另外再去定義，因為是單純去 database 去拉資料過來

  • 好處：就不用透過 api 去拉資料
  • 壞處：當拉的 database，結構有變就必須跟著動到 code
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#models/test/base.rb
class Test::Base < ActiveRecord::Base
  self.abstract_class = true
  ActiveRecord::Base.establish_connection(
    :adapter  => "mysql2",
    :host     => "localhost",
    :username => "root",
    :password => "",
    :database => "database_name"
  )
  end

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#models/test/course.rb
class Test::Course < Test::Base
  self.table_name = :Course
  has_many :teachers, class_name: "Test::Teacher"
end

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#models/test/teacher.rb
class Test::Teacher < Test::Base
  self.table_name = :teacher
  belongs_to :course, class_name: "Test::Course"
end

other

也可以寫在 database.yml 裡面

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development_db2:
  database: your_database_name_development
  <<: *default

test_db2:
  database: your_database_name_test
  <<: *default

production_db2:
  database: your_database_name
  <<: *default

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class OtherDatabase < ActiveRecord::Base
  #記得要用 symbol
  establish_connection "#{RAILS_ENV}_db2".to_sym
end

class User < OtherDatabase
  self.table_name = :user
end

其他文件:

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