在时区找到的Rails - 不工作 [英] Rails in time zone finding - not working

问题描述

我有 CarRoute id：22783，route_time：2016-07-07 05:30 ：00
，但在 CarRoute.find_by_id（22783）.route_time是星期四，07七月2016 07:30:00 CEST +02：00

所以rails添加2h，但是当我想要通过时间找到此路由不起作用时，

  CarRoute.where（：id => 22783，：route_time => DateTime.new（Date.today.year，Date.today.month，Date.today.day，7，0 ，0，0）.. DateTime.new（Date.today.year，Date.today.month，Date.today.day，19，0，0，0））
 => [] 
  

Enyone知道如何找到这个？

解决方案

Rails将所有内容存储在UTC中，这意味着在分配datetime时使用的任何时区，都将转换为UTC。当活动记录加载新记录时，该日期将显示在当前时区（Time.zone）中，这就是为什么执行 CarRoute.find_by_id（22783）.route_time 得到一个CEST日期，但如果你去你的数据库，你会看到一个UTC的日期。

以下内容应该让你清楚：

 > Time.zone 
 => ＃< ActiveSupport :: TimeZone：0x007ff6bd390100 @ name =UTC，@ utc_offset = nil，@tzinfo =＃< TZInfo :: DataTimezone：Etc / UTC>> 
> a = Account.first 
 => ＃<帐户ID：6 ..... 
> a.updated_at 
 => Wed，06 Jul 2016 18:47:32 UTC +00：00 
> Time.zone =EST
 => EST
> a.reload 
 ... 
> a.updated_at 
 =>星期三，06七月2016 13:47:32 EST -05：00 
  

当您使用 DateTime.new 日期在utc中创建：

 > d = DateTime.new（2016,7,7）
 =>星期四，07七月07 00 00:00:00 +0000 
> d.utc？ 
 =>真
> a.updated_at.utc？ 
 => false 
  

在你的哪里查询，你从7 UTC开始，这是上午9点CEST。尝试一下：

  DateTime.new（2016,7,7,7,0,0,0）.change（offset ：'CEST'）
  

I have problem with zones in rails.

I have CarRoute id: 22783, route_time: "2016-07-07 05:30:00" but in CarRoute.find_by_id(22783).route_time is Thu, 07 Jul 2016 07:30:00 CEST +02:00

So rails add 2h but when I want find by time this route is not works,

CarRoute.where(:id=>22783,:route_time=> DateTime.new(Date.today.year, Date.today.month, Date.today.day, 7, 0, 0, 0)..DateTime.new(Date.today.year, Date.today.month,  Date.today.day, 19, 0, 0, 0)) 
 => []

Enyone know how find this ?

解决方案

Rails stores everything in UTC, which means that whatever time zone you use when assigning a datetime, its converted to UTC. When active record loads a new record, that date is presented in the current time zone (Time.zone), that's why when you perform CarRoute.find_by_id(22783).route_time you get a CEST date, but if you go to your database you will see a UTC date.

The following should make it clear for you:

> Time.zone
  => #<ActiveSupport::TimeZone:0x007ff6bd390100 @name="UTC", @utc_offset=nil, @tzinfo=#<TZInfo::DataTimezone: Etc/UTC>>
> a = Account.first
  => #<Account id: 6 .....
> a.updated_at
  => Wed, 06 Jul 2016 18:47:32 UTC +00:00
> Time.zone = "EST"
  => "EST"
> a.reload
  ...
> a.updated_at
  => Wed, 06 Jul 2016 13:47:32 EST -05:00  

When you use DateTime.new the date is created in utc:

> d = DateTime.new(2016,7,7)
  => Thu, 07 Jul 2016 00:00:00 +0000
> d.utc?
  => true
> a.updated_at.utc?
  => false 

In your where query, you're starting at 7 UTC, which is 9 am CEST. Try something like:

DateTime.new(2016,7,7,7,0,0,0).change(offset: 'CEST')

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