Rails 3、创建主记录后如何添加关联记录(Books、Auto Add BookCharacter) [英] Rails 3, how add a associated record after creating a primary record (Books, Auto Add BookCharacter)

问题描述

Rails 新手...试图了解做事的正确方式...

Rails newbie... trying to understand the right way to do things...

在我的应用程序中，用户可以创建一本书(我有这本书)

In my app users can create a Book ( I have that working)

我想要发生的是当用户创建一本书时，将一条记录添加到 BookCharacters 表中，例如 (id, book.id, user.id, characterdescription.string.)

What I want to happen is when a user creates a book, a record is added to the BookCharacters Table, something like (id, book.id, user.id, characterdescription.string.)

创建图书时，应自动将创建它的用户添加为第一个 BookCharacter.之后，用户可以根据需要手动添加/编辑任意数量的 BookCharacters.但最初我希望它们默认自动添加.

When the book is created, the user who created it should automatically be added as the first BookCharacter. After than the user can then manually add/edit as many BookCharacters as they want. But initially I want them added automatically by default.

所以在我的 Book 控制器中，我有:

So in my Book controller I have:

def create
 @book = Book.new(params[:book])
 respond_to do |format|
  if @book.save
....

有了Rails，是不是在书保存后添加那种逻辑的做法?类似的东西

With Rails, is it the practice to add that kind of logic after the book is saved? Something like

Book.create( :creator => current_user.id)

感谢您的帮助

推荐答案

需要理解的重要一点是 Rails 使用 ActiveRecord 实现关系的约定.一本书有很多字符，每个字符属于一本书，所以:

The important thing to understand is the convention by which Rails implements relationships using ActiveRecord. A book has many characters, and each character belongs to a book, so:

class Book < ActiveRecordBase
  has_many :characters
end

class Character < ActiveRecordBase
  belongs_to :book
end

Rails 现在假设 characters 表将有一个名为 book_id 的外键，它与 books 表相关.创建属于一本书的角色:

Rails now assumes that the characters table will have a foreign key called book_id, which relates to the books table. To create a character belonging to a book:

@book = Book.new(:name=>"Book name")
@character = @book.characters.build(:name=>"Character name")

现在当保存 @book 时(假设 @book 和 @character 都有效)，将在两个books 和 characters 表，其中字符行通过 book_id 链接.

Now when @book is saved (assuming both @book and @character are valid), a row will be created in both the books and the characters tables, with the character row linked through book_id.

要显示角色也属于用户，您可以将该关系添加到角色模型中:

To show that a character also belongs to a user, you could add that relationship to the Character model:

class Character < ActiveRecordBase
  belongs_to :book
  belongs_to :user
end

因此 Rails 现在期望 characters 也有名为 user_id 的外键，它指向一个 users 表(它也需要一个 用户模型).创建角色时指定用户:

Thus Rails now expects characters to also have foreign key called user_id, which points to a users table (which also needs a User model). To specify the user when creating the character:

@book = Book.new(:name=>"Book name")
@character = @book.characters.build(:name=>"Character name",:user=>current_user)

也可以通过调用对象上的相应方法来分配外键:

You can also assign the foreign key by calling the corresponding method on the object:

@character.user = current_user

这一切都有效，因为它遵循 Rails 命名模型和表的约定.您可以背离这些约定，但如果这样做，您将更难学习 Rails.

This all works because it follows the Rails conventions for naming models and tables. You can depart from these conventions, but you'll have a harder time learning Rails if you do.

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