数据库中的Rails存储阵列

Question

I need to persist an array in my rails language learning app. Here is the situation/reason I need to do this (if there is a better way please let me know). The user is presented, one at a time, 10 words to learn. After the words are learned they get quized on the same set of 10 words.

For the 'quiz' portion I would like to randomize the order the words appear in (for example: currently if you learn the words 1.fish 2.cat 3.dog... you will be quized in the same order 1.fish 2.cat 3.dog... which can make the quiz easier.

I need to persist it in case the user were to log off or navigate away. In this instance I want to return them to the exact word they left off on the quiz.

Here is the controller code I currently have:

def index 
  .
  .
  @quiz = Lang.limit(10).offset(current_user.bookmark - 11)  
  exercise_bank
  .
  .    
end

private
  def exercise_bank
    current_user.random_exercise_array = (0..9).step(1).shuffle
    current_user.save
    @index2 = current_user.random_exercise_array[@index] 
    #@index starts at 0 and increments on each call to index action
    #@index2 grabs the random number and uses it to reference a word in @quiz
    #something like this: @quiz[@index2].spanish_to_english---grabs a english word
  end
end

The idea of the above is to pick a random number 0-9 and use it to reference a word in my DB. The above results in something like the following in my DB for the random_exercise_array attribute:

random_exercise_array: "---\n- 6\n- 0\n- 1\n- 7\n- 8\n- 5\n- 9\n- 3\n- 2\n- 4\n"

Here is the relevant User DB code:

class DeviseCreateUsers < ActiveRecord::Migration
  serialize :random_exercise_array
end

Relevant migration file:

class AddRandomExerciseArrayToUsers < ActiveRecord::Migration
  def change
    add_column :users, :random_exercise_array, :text
  end
end

Is this the best way to solve this problem? If so, can you explain how to get back an integer from random_exercise_array without all of the (-)'s and (\\n')s?

Answer 1

If you want get an array back from DB text column, you should declare the type in your user model like this:

class DeviseCreateUsers < ActiveRecord::Base  #why your original code inherit from ActiveRecord::Migration?
  serialize :random_exercise_array, Array
end

Then you can use current_user.random_exercise_array as an array instead of a string.