扩展迁移设置表外键

ruby 代码

module MigrationHelpers
  def foreign_key(from_table, from_column, to_table)
    constraint_name = "fk_#{from_table}_{from_column}"

    execute %{
      alter table #{from_table}
      add constraint #{constraint_name}
      foreign key (#{from_column})
      references #{to_table}(id)
    }
  end
end

ruby 代码

require "migration_helpers"
class CreateLineItems < ActiveRecord::Migration
  extend MigrationHelpers

  def self.up
    foreign_key(:line_items, :product_id, :products)
  end
end