Ruby on Rails 生成模型 field:type - field:type 有哪些选项？

Ruby on Rails generates model field:type - what are the options for field:type?

提问by Meltemi

I'm trying to generate a new model and forget the syntax for referencing another model's ID. I'd look it up myself, but I haven't figured out, among all my Ruby on Rails documentation links, how to find the definitive source.

我正在尝试生成一个新模型，但忘记了引用另一个模型 ID 的语法。我会自己查找，但我还没有弄清楚，在我所有的 Ruby on Rails 文档链接中，如何找到最终的来源。

$ rails g model Item name:string description:text(and here either reference:productor references:product). But the better question is whereor howcan I look for this kind of silliness easily in the future?

$ rails g model Item name:string description:text（这里无论是reference:product或references:product）。但更好的问题是，我将来在哪里或如何轻松地寻找这种愚蠢？

Note: I've learned the hard way that if I mistype one of these options and run my migrationthen Ruby on Rails will totally screw up my database... and rake db:rollbackis powerless against such screwups. I'm sure I'm just not understanding something, but until I do... the "detailed" information returned by rails g modelstill leaves me scratching...

注意：我已经学会了一种艰难的方式，如果我错误地输入了这些选项之一并运行我的迁移，那么 Ruby on Rails 将完全搞砸我的数据库......并且rake db:rollback对这种搞砸无能为力。我确定我只是不理解某些东西，但是在我理解之前......返回的“详细”信息rails g model仍然让我抓挠......

回答by Paul Schreiber

:primary_key, :string, :text, :integer, :float, :decimal, :datetime, :timestamp,
:time, :date, :binary, :boolean, :references

See the table definitionssection.

请参阅表定义部分。

回答by Troy

To create a model that references another, use the Ruby on Rails model generator:

要创建引用另一个模型的模型，请使用 Ruby on Rails 模型生成器：

$ rails g model wheel car:references

That produces app/models/wheel.rb:

这会产生app/models/wheel.rb：

class Wheel < ActiveRecord::Base
  belongs_to :car
end

And adds the following migration:

并添加以下迁移：

class CreateWheels < ActiveRecord::Migration
  def self.up
    create_table :wheels do |t|
      t.references :car

      t.timestamps
    end
  end

  def self.down
    drop_table :wheels
  end
end

When you run the migration, the following will end up in your db/schema.rb:

当您运行迁移时，以下内容将最终出现在您的db/schema.rb 中：

$ rake db:migrate

create_table "wheels", :force => true do |t|
  t.integer  "car_id"
  t.datetime "created_at"
  t.datetime "updated_at"
end

As for documentation, a starting point for rails generators is Ruby on Rails: A Guide to The Rails Command Linewhich points you to API Documentationfor more about available field types.

至于文档，rails 生成器的起点是Ruby on Rails：Rails 命令行指南，它指向API 文档以获取有关可用字段类型的更多信息。

回答by B Seven

$ rails g model Item name:string description:text product:references

$ rails g model Item name:string description:text product:references

I too found the guides difficult to use. Easy to understand, but hard to find what I am looking for.

我也发现这些指南很难使用。容易理解，但很难找到我要找的东西。

Also, I have temp projects that I run the rails generatecommands on. Then once I get them working I run it on my real project.

另外，我有运行rails generate命令的临时项目。然后一旦我让他们工作，我就会在我的真实项目中运行它。

Reference for the above code: http://guides.rubyonrails.org/getting_started.html#associating-models

以上代码参考：http: //guides.rubyonrails.org/getting_started.html#associating-models

回答by Raghu

http://guides.rubyonrails.orgshould be a good site if you're trying to get through the basic stuff in Ruby on Rails.

如果您想了解 Ruby on Rails 的基本内容，http://guides.rubyonrails.org应该是一个不错的站点。

Here is a link to associate models while you generate them: http://guides.rubyonrails.org/getting_started.html#associating-models

这是在生成模型时关联模型的链接：http: //guides.rubyonrails.org/getting_started.html#associating-models

回答by Victor Augusto

Remember to not capitalize your text when writing this command. For example:

请记住，在编写此命令时不要将文本大写。例如：

Do write:

写：

rails g model product title:string description:text image_url:string price:decimal

Do not write:

不要写：

rails g Model product title:string description:text image_url:string price:decimal

At least it was a problem to me.

至少对我来说是个问题。

回答by justinedps26

I had the same issue, but my code was a little bit different.

我有同样的问题，但我的代码有点不同。

def new
 @project = Project.new
end

And my form looked like this:

我的表格是这样的：

<%= form_for @project do |f| %>
     and so on....
<% end %>

That was totally correct, so I didn't know how to figure it out.

这是完全正确的，所以我不知道如何弄清楚。

Finally, just adding

最后，只需添加

url: { projects: :create }

after

后

<%= form-for @project ...%>

worked for me.

对我来说有效。

回答by chandanjha

It's very simple in ROR to create a model that references other.

在 ROR 中创建引用其他模型的模型非常简单。

rails g model Item name:string description:text product:references

rails g 模型项目名称：字符串描述：文本产品：参考

This code will add 'product_id' column in the Item table

此代码将在 Item 表中添加“product_id”列

回答by chandanjha

There are lots of data types you can mention while creating model, some examples are:

在创建模型时，您可以提及很多数据类型，一些示例是：

:primary_key, :string, :text, :integer, :float, :decimal, :datetime, :timestamp, :time, :date, :binary, :boolean, :references

syntax:

句法：

field_type:data_type