ActiveRecord的配置错误- ActiveRecord::AdapterNotSpecified

Question

为什么程序不能运行？

list.rb

require 'active_record'
require 'yaml'

ActiveRecord::Base.configurations = YAML.load_file('./database.yml')
ActiveRecord::Base.establish_connection('development')

class Student < ActiveRecord::Base
end

student = Student.find('123')
puts student.id
puts student.name

database.yml

default: &default
  adapter: sqlite3
  encoding: unicode
  pool: 5

development:
  <<: *default
  database: my_database_name

list.db

sqlite> select *从学生；

123|foo|foo@email.com

错误

../activerecord-5.0.0.1/lib/active_record/connection_adapters/connection_specification.rb:170:in `spec': database configuration does not specify adapter (ActiveRecord::AdapterNotSpecified)

Answer 1

在我的例子中，我使用一个字符串来标识我想要使用的数据库配置，而不是一个符号(这似乎是Rails5所需要的)

试试这个：

ActiveRecord::Base.establish_connection(:development)