From: Leslie Viljoen <leslieviljoen@...>
Date: 2006-11-22T07:42:53+09:00
Subject: Re: Active Record out of rails: still assumes id?

On 11/21/06, Gabriele Marrone <gabriele.marrone@gmail.com> wrote:
>
> On 21/nov/06, at 14:12, Chris Gallagher wrote:
>
> > This is clearly due to the fact that I dont have any id fields in my
> > database as i thought that active record would do something similar to
> > rails and that i wouldnt have to define them? Obviously this isnt
> > quite
> > the case?
>
> I guess your table will have a key, anyway. You just have to tell
> ActiveRecord what is the key column, as in:
>
> class Person < ActiveRecord::Base
>    set_primary_key :full_name  # overrides id with full_name
> end
>
> Some times you will need a composite primary key, but ActiveRecord
> doesn't support them by default. If you need them, however, you can
> install the composite_primary_keys gem (http://
> compositekeys.rubyforge.org/) and then do something like this:
>
> class Person < ActiveRecord::Base
>    set_primary_keys :first_name, :last_name
> end


Though if you do use set_primary_key, remember that in the model
object, the field will still be called 'id' even though it's mapped to
another column in the table. You also then assume responsibility for
incrementing and setting that ID before every save, since the ID can
be in any format.

I have:


class ArchiveLog < MsSqlTable
  set_table_name "ArchiveLog"
  set_primary_key "ArchiveLogID"
end

...

    next_id = ArchiveLog.maximum(:ArchiveLogID)
    if next_id.nil?
      next_id = 0
    else
      next_id += 1
    end

    archiveLog = ArchiveLog.new
    archiveLog.id = next_id
    archiveLog.ArchiveDate = @startTime
    archiveLog.CurrentDataStartDate = @archiveBorderTime

..etc.


Les


-- 
Man's unfailing capacity to believe what he prefers to be true rather
than what the evidence shows to be likely and possible has always
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our childish mistakes, and in the face of mountains of evidence to the
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