Rails Active Record find (: all, : order =>) 문제

Rails Active Record find (: all, : order =>) 문제

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한 번에 두 개 이상의 열에 대해 ActiveRecord :: Base.find 옵션을 사용할 수없는 것 같습니다.

예를 들어, 날짜 및 참석 열이있는 "표시"모델이 있습니다.

다음 코드를 실행하면 :

@shows = Show.find(:all, :order => "date")

다음과 같은 결과를 얻습니다.

[#<Show id: 7, date: "2009-04-18", attending: 2>, 
 #<Show id: 1, date: "2009-04-18", attending: 78>, 
 #<Show id: 2, date: "2009-04-19", attending: 91>, 
 #<Show id: 3, date: "2009-04-20", attending: 16>,
 #<Show id: 4, date: "2009-04-21", attending: 136>]

다음 코드를 실행하면 :

@shows = Show.find(:all, :order => "attending DESC")

[#<Show id: 4, date: "2009-04-21", attending: 136>,
 #<Show id: 2, date: "2009-04-19", attending: 91>,
 #<Show id: 1, date: "2009-04-18", attending: 78>,
 #<Show id: 3, date: "2009-04-20", attending: 16>,
 #<Show id: 7, date: "2009-04-18", attending: 2>]

그러나 내가 실행하면 :

@shows = Show.find(:all, :order => "date, attending DESC")

또는

@shows = Show.find(:all, :order => "date, attending ASC")

또는

@shows = Show.find(:all, :order => "date ASC, attending DESC")

날짜별로 정렬하는 것과 동일한 결과를 얻습니다.

 [#<Show id: 7, date: "2009-04-18", attending: 2>, 
 #<Show id: 1, date: "2009-04-18", attending: 78>, 
 #<Show id: 2, date: "2009-04-19", attending: 91>, 
 #<Show id: 3, date: "2009-04-20", attending: 16>,
 #<Show id: 4, date: "2009-04-21", attending: 136>]

나는 이러한 결과를 얻고 싶습니다.

[#<Show id: 1, date: "2009-04-18", attending: 78>,
#<Show id: 7, date: "2009-04-18", attending: 2>, 
 #<Show id: 2, date: "2009-04-19", attending: 91>, 
 #<Show id: 3, date: "2009-04-20", attending: 16>,
 #<Show id: 4, date: "2009-04-21", attending: 136>]

다음은 로그에서 생성되는 쿼리입니다.

[4;35;1mUser Load (0.6ms)[0m   [0mSELECT * FROM "users" WHERE ("users"."id" = 1) LIMIT 1[0m
[4;36;1mShow Load (3.0ms)[0m   [0;1mSELECT * FROM "shows" ORDER BY date ASC, attending DESC[0m
[4;35;1mUser Load (0.6ms)[0m   [0mSELECT * FROM "users" WHERE ("users"."id" = 1) [0m

마지막으로 내 모델은 다음과 같습니다.

  create_table "shows", :force => true do |t|
    t.string   "headliner"
    t.string   "openers"
    t.string   "venue"
    t.date     "date"
    t.text     "description"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.decimal  "price"
    t.time     "showtime"
    t.integer  "attending",   :default => 0
    t.string   "time"
  end

내가 무엇을 놓치고 있습니까? 내가 도대체 ​​뭘 잘못하고있는 겁니까?

업데이트 : 모든 도움을 주셔서 감사합니다.하지만 여러분 모두 저만큼이나 당황한 것 같습니다. 문제를 해결 한 것은 실제로 데이터베이스를 전환하는 것이 었습니다. 기본 sqlite3에서 mysql로 ​​전환했습니다.

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I notice that in your first example, the simple :order => "date", record 7 is sorted before record 1. This order is also how you see the results in the multi-column sort, regardless of whether you sort by attending.

This would seem to make sense to me if the dates weren't exactly the same, and the date for 7 is before the date for 1. Instead of finding that the dates are exactly equal then proceeding to sort by attending, the query finds that the dates are not equal and simply sorts by that like all the other records.

I see from browsing around that SQLite doesn't have a native understanding of DATE or DATETIME data types and instead gives users the choice of floating point numbers or text that they must parse themselves. Is it possible that the literal representation of the dates in the database are not exactly equal? Most people seem to need to use date functions so that dates behave like you would expect. Perhaps there's a way to wrap your order by column with a date function that will give you something concrete to compare, like date(date) ASC, attending DESC. I'm not sure that syntax works, but it's an area to look at for solving your problem. Hope that helps.

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Could be two things. First,

This code is deprecated:

Model.find(:all, :order => ...)

should be:

Model.order(...).all

Find is no longer supported with the :all, :order, and many other options.

Second, you might have had a default_scope that was enforcing some ordering before you called find on Show.

Hours of digging around on the internet led me to a few useful articles that explain the issue:

• http://m.onkey.org/active-record-query-interface
• http://www.simonecarletti.com/blog/2010/07/the-way-to-rails-3/

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The problem is that date is a reserved sqlite3 keyword. I had a similar problem with time, also a reserved keyword, which worked fine in PostgreSQL, but not in sqlite3. The solution is renaming the column.

See this: Sqlite3 activerecord :order => "time DESC" doesn't sort

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I just ran into the same problem, but I manage to have my query working in SQLite like this:

@shows = Show.order("datetime(date) ASC, attending DESC")

I hope this might help someone save some time

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isn't it only :order => 'column1 ASC, column2 DESC'?

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Make sure to check the schema at the database level directly. I've gotten burned by this before, where, for example, a migration was initially written to create a :datetime column, and I ran it locally, then tweaked the migration to a :date before actually deploying. Thus everyone's database looks good except for mine, and the bugs are subtle.

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I understand why the Rails devs went with sqlite3 for an out-of-the-box implementation, but MySQL is so much more practical, IMHO. I realize it depends on what you are building your Rails app for, but most people are going to switch the default database.yml file from sqlite3 to MySQL.

Glad you resolved your issue.

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It is good that you've found your solution. But it is an interesting problem. I tried it out myself directly with sqlite3 (not going through rails) and did not get the same result, for me the order came out as expected.

What I suggest you to do if you want to continue digging in this problem is to start the sqlite3 command-line application and check the schema and the queries there:

This shows you the schema: .schema

And then just run the select statement as it showed up in the log files: SELECT * FROM "shows" ORDER BY date ASC, attending DESC

That way you see if:

1. The schema looks as you want it (that date is actually a date for instance)
2. That the date column actually contains a date, and not a timestamp (that is, that you don't have a time of the day that messes up the sort)

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This might help too:

Post.order(created_at: :desc)

참고URL : https://stackoverflow.com/questions/742700/rails-active-record-findall-order-issue