Rails更新海量数据

Question

I have one model call DataIndicator , it contains daily data,

And It has the following column.

:id => :integer,
:date => :datetime,
:dau => :integer,
:login_count => :integer

It had many data, but now I need to change some of it.

How do I massive update its value by date?

EX:

The original

{ "id" => 1, "date" => 2017-01-01 00:00:00 UTC, "dau" => 5 , "login_count" => 150 }, 
{ "id" => 2, "date" => 2017-01-02 00:00:00 UTC, "dau" => 5 , "login_count" => 140 },
{ "id" => 3, "date" => 2017-01-03 00:00:00 UTC, "dau" => 5 , "login_count" => 300 }

Now I have a hash value, which would be referred to modify the original data.

Like this

update_date = {
  "2017-01-01" => {
    "dau" => 5,
    "login_count" => 5,
  },
  "2017-01-02" => {},
  "2017-01-03" => {
    "dau" => 5,
  },
  ...
}

As you can see, the update_date will not contain all attributes, it may only have one or even zero new data. What is the best way to update this value?

I can only think about the bad one.

Like this

update_date.each do |k, v|
  data_by_date = DataIndicator.where(date: DateTime.parse(k)).first
  next if data_by_date.nil? 
  data_by_date.update(v)
end

Answer 1

I think I misread your question. Wouldn't it be easier if you just picked all DataIndicator records and then checked if the hash contained data for it?

DataIndicator.all.each do |di|
  date =  di.date.strftime("%Y-%m-%d")
  to_update = update_date[date]
  next if to_update.blank?
  to_update.each do |field,value|
    di.send("#{field}=".to_sym, value)
  end
  di.save!
end

Answer 2

This works for me.
For Rails 4+

DataIndicator.where(["date(date) = ?"], "2017-01-01").update_all(dau: 5, login_count: 5)