Rails：添加迁移以添加数组（默认为空） [英] Rails: Adding migration to add an array (default empty)

问题描述

我正在尝试向我的资源之一添加一个名为share的列。
的想法是用户可以上传文档并与其他（特定）用户共享文档，并且该数组包含用户想要与之共享的电子邮件。

I'm trying to add a column called share to one of my resources. The idea is that users can upload documents and share them with other (specific) users, and the array contains the emails of those that the user wants to share with.

我尝试使用代码添加迁移

I tried adding a migration with the code

class AddShareToDocuments < ActiveRecord::Migration
  def change
    add_column :documents, :share, :array, :default => []
  end
end

但是当我在命令提示符，它说share：nil和user.document.share.class是NilClass。

But when I open up rails console in the command prompt, it says that share:nil and user.document.share.class is NilClass.

通过在rails控制台沙箱中键入

Creating a new array in the rails console sandbox by typing

newarray = []

说newarray.class是数组。

says that newarray.class is Array.

有人可以发现我在做什么错吗？

Can anyone spot what I'm doing wrong?

推荐答案

设置4种PostgreSQL数组数据类型

Rails 4 the PostgreSQL Array data type

在终端

$ rails generate migration AddTagsToProduct tags:string

迁移文件：

class AddTagsToProduct < ActiveRecord::Migration
  def change
    add_column :products, :tags, :string, array: true, default: []
  end
end

https://coderwall.com/p/sud9ja/rails-4-the-postgresql-array-data-type

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