Question

我是红宝石的新手。我正在尝试使用sqlite3。我有2个表书和用户，用户可以拥有属于用户的manty书和书籍，这是在程序中建立的。但是当我运行mu文件时，我得到以下错误程序文件（x86）/Ruby200-x64/lib/ruby/gems/2.0.0/gems/activerecord-active_record/connection_adapters/sqlite3_adapter.rb:511:in table_structure': Could not find table 'libusers' (ActiveRecord::StatementInvalid) from C:/Program Files (x86)/Ruby200-x64/lib/ruby/gems/2.0.0/gems/activerecord-4.2.4/lib/active_record/connection_adapters/sqlite3_adapter.rb:385:in列＆＃39; 来自C：/ Program Files（x86）/Ruby200-x64/lib/ruby/gems/2.0.0/gems/activerecord-4.2.4/lib/active_record/connection_adapters/schema_cache.rb:43:in columns' from C:/Program Files (x86)/Ruby200-x64/lib/ruby/gems/2.0.0/gems/activerecord-4.2.4/lib/active_record/attributes.rb:93:in列＆＃39; 从C：/ Program Files（x86）/Ruby200-x64/lib/ruby/gems/2.0.0/gems/activerecord-4.2.4/lib/active_record/attributes.rb:98:in columns_hash' from C:/Program Files (x86)/Ruby200-x64/lib/ruby/gems/2.0.0/gems/activerecord-4.2.4/lib/active_record/inheritance.rb:205:in subclass_from_attributes？＆＃39; 从C：/ Program Files（x86）/Ruby200-x64/lib/ruby/gems/2.0.0/gems/activerecord-4.2.4/lib/active_record/inheritance.rb:54:in new' from C:/Program Files (x86)/Ruby200-x64/lib/ruby/gems/2.0.0/gems/activerecord-4.2.4/lib/active_record/persistence.rb:33:in创建＆＃ 39;

我读到了这些错误并运行了rake db：migrate它说没有找到rake文件我被困住了，需要帮助

require 'active_record'
require 'sqlite3'
 `enter code here`ActiveRecord::Base.establish_connection(:adapter =>    "sqlite3",:database => "memory")
  class Clean < ActiveRecord::Migration 
   def self.up
   #ActiveRecord::Schema.define do
   create_table :users do |table|
  table.column :name, :string
  table.column :age, :integer
  table.column :books_borrowed,:integer 
     end
  create_table :books do |table|
  table.column :borrower, :string
   table.column :title, :string
  table.column :borrow_date, :string
  table.column :due_date, :string
 end
  end
  def self.down
  drop_table :users
   drop_table :books
  end 
end
class Libuser < ActiveRecord::Base
 has_many :books
end
class Books< ActiveRecord::Base
 belongs_to :user
end
#Clean.down
Clean.up

user= Libuser.create(:name=>"Megna", :age=>25, :books_borrowed=>2 )
user.books.create(:title=>"immortals of meluha", :borrow_date=>"12 jan 2015", :due_date=>"22 jan 2015")
user.books.create(:title=>"secret of nagas", :borrow_date=>"24 jan 2015", :due_date=>"2 Feb 2015")

user= Libuser.create(:name=>"sandhya", :age=>27, :books_borrowed=>3 )
user.books.create(:title=>"ugly duckling ", :borrow_date=>"12 feb 2015", :due_date=>"22 feb 2015")
user.books.create(:title=>"Little red riding Hood", :borrow_date=>"24 march 2015", :due_date=>"2 april 2015")
user.books.create(:title=>"Little red riding Hood", :borrow_date=>"12 april 2015", :due_date=>"22 april 2015

＆＃34）

提前致谢

Answer 1

您的桌子被称为＆＃34;用户＆＃34;而不是＆＃34; Libusers＆＃34;。如果用User替换Libuser它是否有效？

对于＆＃34; Libuser＆＃34;要工作，你需要在数据库中使用一个名为Libusers的表。

注意复数 - 您的ActiveRecord模型应该是单数（用户，书籍），并且您的表名应该是复数（用户，书籍）。

Answer 2

默认情况下，active_record假定类MyModel（单数，camelcase）映射到数据库表my_models（复数，下划线），因此Libuser应映射到表{{1 }}，而不是libusers。

如果您真的希望users映射到Libuser（为什么？），您可以这样做：

users

ruby

2 个答案: