如何在MySQL的Ruby哈希中存储多个电子邮件？

Question

I built my own comments in my rails app without threading and I want to be able to send reply all notifications for new comments on a project. Would it be best to just store emails into a ruby hash in MySQL and then read from it when necessary? I'm trying to figure out how to insert emails into a hash with keys I don't have to define, any help?

Answer 1

Assuming you have some column with string type in some mysql table.

Use json gem. If you don't have json gem install it by gem install json .

require 'json'
reply_emails_list = ["a@gmail.com", "b@gamil.com"]
obj.column_name = {:emails => reply_emails_list}.to_json  #storing ruby hash as string in mysql

To get ruby hash back use `JSON.parse(obj)'

emails_list = JSON.parse(obj.column_name)  #ruby hash

or

In rails way. In model you can do like this:

YourModel < ActiveRecord::Base
  serialize :column_name, Array  #If don't want hash
  serialize :column_name     #you can store key value pair as I shown above
end

Using second will avoid converting from hash to json and vice versa

Answer 2

In Postgres, there is an array extension you can use to get actual array storage. Unfortunately, this doesn't work for MySQL.

The best thing for data like e-mails would be to serialize your list of emails as a String field and provide a synthetic attribute that provides an array accessor (if needed). You can then put callbacks on your comment to update the email list when Comments are added to this Project.

class Project < ActiveRecord::Base
  # db String field email_list
  attr_accessor :emails

  def emails
    email_list.split(',')
  end

  def emails=(email_ary)
    self.email_list = email_ary.join(',')
  end
end

This can be a good alternative to using a JSON blob, as it allows easier text searching and handling of a comma separated list. I don't know if split() or JSON.parse provide an advantage in terms of serialization performance.

Answer 3

According to ActiveRecord::Base you can serialize a column:

class MyModel < ActiveRecord::Base
  serialize :emails
end

User.create(:emails => %w( email1@a.com email2@b.com email3@c.com )