从Rails控制台生成行和列

Question

I have a small predicament.

I have a table called users. The table users has relationship with another table called user notification. Here is the migration for the user table:

create_table "user_notifications", force: :cascade do |t|
    t.belongs_to :user
    t.integer "other_user"
    t.integer  "unseen_count",    default: 0
    t.datetime "created_at",                  null: false
    t.datetime "updated_at",                  null: false
  end

The problem is that when I create a new user then the table is populated with the row of the new user. How do I add the row to all the existing users. It is needed for the function of the app. Also I am using putty to connect to the server so the only tool I have is the rails console.

Example: I have 60 users. How do I have it so all 60 users get a row in the new table using the rails console.

Edit: This is the method I use whenever a user is signed up. Can I use this method within the rails console or create a deviation of this?

user.rb:

after_create :create_user_notification    

def create_user_notification
  UserNotification.create(:user_id => self.id)
end

Thank you in advance.

Answer 1

If I understand you correctly you want to add a notification to each user record.

Given that you have models that look something like this:

class User
  has_many :user_notifications
end

class UserNotification
  belongs_to :user
end

To insert a record for each user you would do something like this:

User.all.find_in_batches(batch_size: 10).each do |u|
  u.user_notifications.create(message: 'Hello dear')
end

.find_in_batches might not really matter if you have 60 records but if you have 60,000 your server will run out of memory.