armanx, I think that I found it.
BookReader.first.checkouts.all(links:
[Checkout.relationships[:book].inverse], order:
[DataMapper::Query::Direction.new(Book.properties[:published], :desc)])
freakish
But it retrieves me a collection of Checkout objects, ordered by
:published.desc .
is that what you want ?
so long
http://datamapper.lighthouseapp.com/projects/20609/tickets/1164-manytoone-relationships-form-bad-sql-with-links
2012/9/4 Arthur M. Meskelis
> oh, sorry.
> That's a hard to do.
>
> I found that site
> http://rhnh.net/2010/12/01/ordering-by-a-field-in-a-join-model-with-datamapper
> maybe
> help.
>
> Anyway, I will continue to search.
>
>
> 2012/9/4 armanx
>
>> That doesn't quite accomplish what I'm trying to do.
>>
>> BookReader.first.books.all(:**order => [:published.desc])
>>
>>
>> gives me Books; what I'm after are Checkouts, sorted by Book's :published
>> column
>>
>>
>> On Monday, September 3, 2012 12:54:31 AM UTC-7, armanx wrote:
>>>
>>> I'm looking to sort records in one table, based on a date column in
>>> another table. For example, I have the following tables:
>>>
>>> class BookReader
include DataMapper::Resource
has n, :checkouts
has n, :books, :through => :checkouts
property :id, Serial
property :name, String
property :city, String
end
class Book
include DataMapper::Resource
has n, :checkouts
has n, :readers, :through => :checkouts
property :id, Serial
property :title, String
property :author, String
property :published, Date
end
class Checkout
include DataMapper::Resource
belongs_to :bookreader, :key => true
belongs_to :book, :key => true
property :created_at, DateTime
property :updated_at, DateTime
end
>>>
>>>
>>> (This assumes each BookReader can only check out each Book once).
>>> I can select all the Book objects belonging to a particular BookReader:
>>>
>>> checkouts = BookReader.first.checkouts
>>>
>>>
>>> Now, I want to sort these based on the :published date of the Book
>>> object. E.g.:
>>>
>>> SELECT
c.*, b.date
FROM
"checkouts" as c
JOIN "books" as b on b.id = c.book_id
WHERE
c.bookreader_id = 1
ORDER BY
b.date DESC
>>>
>>>
>>> Any way to do this directly through DM?
>>>
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>
>
>
> --
> --
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>
> E para todas as outras existe RTFM, STFW e LMGTFY
>
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tem preço !
E para todas as outras existe RTFM, STFW e LMGTFY
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