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								<p><strong><a href="/category/web/ruby%20on%20rails">web/ruby on rails</a></strong></p><h3>[Ruby on Rails] ORM rails generate model array column: 모델에 배열 데이터 타입 저장</h3>
								<p><span>네로 neroya
                                <span></span>2021. 10. 20. 23:47
								
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							<div><h2 data-ke-size="size26"><b># rails how to <span>generate model array column</span></b></h2>

<p data-ke-size="size16">model을 만들 때 <b>rails g model</b> 명령어를 사용한다.</p>
<pre id="code_1634044783881" data-ke-language="shell" data-ke-type="codeblock"><code>$ rails g model user Article title:string body:text</code></pre>

<pre id="code_1634045426121" data-ke-language="python" data-ke-type="codeblock"><code>class CreateArticles &lt; ActiveRecord::Migration[6.0]
  def change
    create_table :articles do |t|
      t.string :title
      t.text :body

      t.timestamps
    end
  end
end</code></pre>
<p data-ke-size="size16">위 명령어를 사용하면 위와 같은 Migration 파일이 생성된다.</p>
<p data-ke-size="size16">title은 string 타입으로, body는 text 타입으로 테이블이 생성된다.&nbsp;</p>

<p data-ke-size="size16">아래 명령어를 통해 들어가보면&nbsp;</p>
<pre id="code_1634045607938" data-ke-language="shell" data-ke-type="codeblock"><code>$ rails g model --help</code></pre>
<pre id="code_1634045715639" data-ke-language="shell" data-ke-type="codeblock"><code> Available field types:

    Just after the field name you can specify a type like text or boolean.
    It will generate the column with the associated SQL type. 
    For instance:
    
        `rails generate model post title:string body:text`

    will generate a title column with a varchar type and a body column with a text
    type. If no type is specified the string type will be used by default.
    
    You can use the following types:
        integer
        primary_key
        decimal
        float
        boolean
        binary
        string
        text
        date
        time
        datetime

    You can also consider `references` as a kind of type. 
    For instance, if you run:
    
        `rails generate model photo title:string album:references`
        
    It will generate an `album_id` column. You should generate these kinds of fields when
    you will use a `belongs_to` association, for instance. 
    `references` also supports
    polymorphism, you can enable polymorphism like this:
    
        `rails generate model product supplier:references{polymorphic}`
        
    For integer, string, text and binary fields, an integer in curly braces will
    be set as the limit:
    
        `rails generate model user pseudo:string{30}`
        
    For decimal, two integers separated by a comma in curly braces will be used
    for precision and scale:
    
        `rails generate model product 'price:decimal{10,2}'`
        
    You can add a `:uniq` or `:index` suffix for unique or standard indexes
    respectively:
    
        `rails generate model user pseudo:string:uniq`
        `rails generate model user pseudo:string:index`
        
    You can combine any single curly brace option with the index options:
    
        `rails generate model user username:string{30}:uniq`
        `rails generate model product supplier:references{polymorphic}:index`
        
    If you require a `password_digest` string column for use with
    has_secure_password, you can specify `password:digest`:
    
        `rails generate model user password:digest`
        
    If you require a `token` string column for use with
    has_secure_token, you can specify `auth_token:token`:
    
        `rails generate model user auth_token:token`</code></pre>



<h3 data-ke-size="size23">그런데&nbsp;<b><span>배열 타입</span>의 칼럼을 생성할 수 있지 않을까</b>&nbsp;하는 의문이 들었다 !&nbsp;</h3>

<p data-ke-size="size16"><span><b>1. migration 파일을 만들어준다.</b></span></p>
<pre id="code_1634045829246" data-ke-language="shell" data-ke-type="codeblock"><code>$ rails g migration Article add_subjects_to_article subjects:text</code></pre>
<blockquote data-ke-style="style2">명령어 설명<br>- g: generate =&gt; g migration 하면 migration 파일을 만들어준다. 예) g controller... , g model ... 등등<br>- Article: 대신 Table 명<br>- add_subjects_to_article: 설정하고 싶은 migration 파일 이름<br>- subjects:text: subjects을 text 타입으로</blockquote>
<p data-ke-size="size16"><span><b>2. DB가 PostgreSQL인 경우 migration 파일에 다음과 같이 추가해준다.</b></span></p>
<pre id="code_1634046033776" data-ke-language="python" data-ke-type="codeblock"><code>class AddSubjectsToArticle &lt; ActiveRecord::Migration
  def change
    add_column :articles, :subjects, :text, array: true, default: []
  end
end</code></pre>
<p data-ke-size="size16">여기서 중요한 것은 <b>array: true, default: []</b> 이다. 이 부분을 직접 작성해준다.</p>

<p data-ke-size="size16"><span><b>2-1. DB가 SQLite3인 경우 app&gt; models&gt; article.rb 에서&nbsp;</b></span></p>
<p data-ke-size="size16">클래스 안에 <b>serialize :subjects, Array </b>라고 작성한다.</p>

<p data-ke-size="size16"><span><b>3. migrate를 한다.</b></span></p>
<pre id="code_1634046348642" data-ke-language="python" data-ke-type="codeblock"><code>$ rails db:migrate</code></pre>




<p data-ke-size="size16"><b><span>출처</span></b></p>
<p data-ke-size="size16"><a href="https://stackoverflow.com/questions/32409820/add-an-array-column-in-rails">https://stackoverflow.com/questions/32409820/add-an-array-column-in-rails</a></p>
<figure id="og_1634046059974" contenteditable="false" data-ke-type="opengraph" data-ke-align="alignCenter" data-og-type="website" data-og-title="Add an array column in Rails" data-og-description="How do you declare an array column in Rails? Detail I have the following model rails generate model User address:text but I want a model which can store multiple addresses per user. The following" data-og-host="stackoverflow.com" data-og-source-url="https://stackoverflow.com/questions/32409820/add-an-array-column-in-rails" data-og-url="https://stackoverflow.com/questions/32409820/add-an-array-column-in-rails" data-og-image="https://scrap.kakaocdn.net/dn/cUP2mf/hyLVYaxx8H/9cR9qhBOWqDzp0Yl5wCMXk/img.png?width=316&amp;height=316&amp;face=0_0_316_316"><a href="https://stackoverflow.com/questions/32409820/add-an-array-column-in-rails" target="_blank" rel="noopener" data-source-url="https://stackoverflow.com/questions/32409820/add-an-array-column-in-rails">

<div>
<p data-ke-size="size16">Add an array column in Rails</p>
<p data-ke-size="size16">How do you declare an array column in Rails? Detail I have the following model rails generate model User address:text but I want a model which can store multiple addresses per user. The following</p>
<p data-ke-size="size16">stackoverflow.com</p>
</div>
</a><img src="https://scrap.kakaocdn.net/dn/cUP2mf/hyLVYaxx8H/9cR9qhBOWqDzp0Yl5wCMXk/img.png?width=316&amp;height=316&amp;face=0_0_316_316"></figure>
<p data-ke-size="size16"><a href="http://blog.plataformatec.com.br/2014/07/rails-4-and-postgresql-arrays/" target="_blank" rel="noopener">http://blog.plataformatec.com.br/2014/07/rails-4-and-postgresql-arrays/</a></p>
<figure id="og_1634046163699" contenteditable="false" data-ke-type="opengraph" data-ke-align="alignCenter" data-og-type="article" data-og-title="Rails 4 and PostgreSQL Arrays « Plataformatec Blog" data-og-description="In this post we show how Rails treats PostgreSQL array type, and how to use PL/pgSQL custom functions to do unique validations in PostgreSQL arrays." data-og-host="blog.plataformatec.com.br" data-og-source-url="http://blog.plataformatec.com.br/2014/07/rails-4-and-postgresql-arrays/" data-og-url="http://blog.plataformatec.com.br/2014/07/rails-4-and-postgresql-arrays/" data-og-image="https://scrap.kakaocdn.net/dn/wQ7JG/hyLVVdOVFY/jZogwRiOiHwFtIM1QKtlBk/img.jpg?width=100&amp;height=100&amp;face=0_0_100_100"><a href="http://blog.plataformatec.com.br/2014/07/rails-4-and-postgresql-arrays/" target="_blank" rel="noopener" data-source-url="http://blog.plataformatec.com.br/2014/07/rails-4-and-postgresql-arrays/">

<div>
<p data-ke-size="size16">Rails 4 and PostgreSQL Arrays « Plataformatec Blog</p>
<p data-ke-size="size16">In this post we show how Rails treats PostgreSQL array type, and how to use PL/pgSQL custom functions to do unique validations in PostgreSQL arrays.</p>
<p data-ke-size="size16">blog.plataformatec.com.br</p>
</div>
</a><img src="https://scrap.kakaocdn.net/dn/wQ7JG/hyLVVdOVFY/jZogwRiOiHwFtIM1QKtlBk/img.jpg?width=100&amp;height=100&amp;face=0_0_100_100"></figure>
</div>
							

							
								
							

							


						
					

					

					

					

					

					

					
						
					
				</div></div>

개구린개구리

# rails how to generate model array column
 
model을 만들 때 rails g model 명령어를 사용한다.
$ rails g model user Article title:string body:text
 
class CreateArticles < ActiveRecord::Migration[6.0]
  def change
    create_table :articles do |t|
      t.string :title
      t.text :body
      t.timestamps
    end
  end
end
위 명령어를 사용하면 위와 같은 Migration 파일이 생성된다.
title은 string 타입으로, body는 text 타입으로 테이블이 생성된다. 
 
아래 명령어를 통해 들어가보면 
$ rails g model --help
 Available field types:
    Just after the field name you can specify a type like text or boolean.
    It will generate the column with the associated SQL type. 
    For instance:
    
        `rails generate model post title:string body:text`
    will generate a title column with a varchar type and a body column with a text
    type. If no type is specified the string type will be used by default.
    
    You can use the following types:
        integer
        primary_key
        decimal
        float
        boolean
        binary
        string
        text
        date
        time
        datetime
    You can also consider `references` as a kind of type. 
    For instance, if you run:
    
        `rails generate model photo title:string album:references`
        
    It will generate an `album_id` column. You should generate these kinds of fields when
    you will use a `belongs_to` association, for instance. 
    `references` also supports
    polymorphism, you can enable polymorphism like this:
    
        `rails generate model product supplier:references{polymorphic}`
        
    For integer, string, text and binary fields, an integer in curly braces will
    be set as the limit:
    
        `rails generate model user pseudo:string{30}`
        
    For decimal, two integers separated by a comma in curly braces will be used
    for precision and scale:
    
        `rails generate model product 'price:decimal{10,2}'`
        
    You can add a `:uniq` or `:index` suffix for unique or standard indexes
    respectively:
    
        `rails generate model user pseudo:string:uniq`
        `rails generate model user pseudo:string:index`
        
    You can combine any single curly brace option with the index options:
    
        `rails generate model user username:string{30}:uniq`
        `rails generate model product supplier:references{polymorphic}:index`
        
    If you require a `password_digest` string column for use with
    has_secure_password, you can specify `password:digest`:
    
        `rails generate model user password:digest`
        
    If you require a `token` string column for use with
    has_secure_token, you can specify `auth_token:token`:
    
        `rails generate model user auth_token:token`
 
 
 
그런데 배열 타입의 칼럼을 생성할 수 있지 않을까 하는 의문이 들었다 ! 
 
1. migration 파일을 만들어준다.
$ rails g migration Article add_subjects_to_article subjects:text
명령어 설명
- g: generate => g migration 하면 migration 파일을 만들어준다. 예) g controller... , g model ... 등등
- Article: 대신 Table 명
- add_subjects_to_article: 설정하고 싶은 migration 파일 이름
- subjects:text: subjects을 text 타입으로
2. DB가 PostgreSQL인 경우 migration 파일에 다음과 같이 추가해준다.
class AddSubjectsToArticle < ActiveRecord::Migration
  def change
    add_column :articles, :subjects, :text, array: true, default: []
  end
end
여기서 중요한 것은 array: true, default: [] 이다. 이 부분을 직접 작성해준다.
 
2-1. DB가 SQLite3인 경우 app> models> article.rb 에서 
클래스 안에 serialize :subjects, Array 라고 작성한다.
 
3. migrate를 한다.
$ rails db:migrate
 
 
 
 
출처
https://stackoverflow.com/questions/32409820/add-an-array-column-in-rails
http://blog.plataformatec.com.br/2014/07/rails-4-and-postgresql-arrays/

[Ruby on Rails] ORM rails generate model array column: 모델에 배열 데이터 타입 저장

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