t.belongs_to在迁移

问题描述

我使用的是Ryan Bates的＃ 141，以创建一个简单的购物车。在其中一个迁移中，他列出

I was using Ryan Bates's source code for railscasts #141 in order to create a simple shopping cart. In one of the migrations, he lists

class CreateProducts < ActiveRecord::Migration
  def self.up
    create_table :products do |t|
      t.belongs_to :category
      t.string :name
      t.decimal :price
      t.text :description
      t.timestamps
    end
  end

  def self.down
    drop_table :products
  end
end

以下是产品型号：

class Product < ActiveRecord::Base
 belongs_to :category
end

c $ c> t.belongs_to：category 行？是 t.integer category_id

What is the t.belongs_to :category line? Is that an alias for t.integer category_id?

推荐答案

code> t.belongs_to：category 只是一个。

The t.belongs_to :category is just a special helper method of rails passing in the association.

如果您查看 belongs_to 实际上是引用的别名

If you look in the source code belongs_to is actually an alias of references

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