Forum: Ruby on Rails Strange behaviour

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sigvei (Guest)
on 2008-11-17 15:16
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I have the following relationships:

Document :has_many Proposals :has_many ProposalVersions.

This fails:
>> Document.first.proposals.first.proposal_versions.size
=> 0

But this works:
>> Proposal.find(1).proposal_versions.size
=> 2

Here's the SQL from the first statement:

SELECT count(*) AS count_all FROM "proposal_versions" WHERE
("proposal_versions".proposal_id = 2)

The failing SQL in the first example seems really dangerous, because
it apparently picks an ID at random (and this obviously works also
with non-count queries, resulting in possibly returning the wrong set
of data:

Where does the '2' come from? Neither Document or Proposal has ID 2,
they're both ID 1.

Is this expected behaviour?

I'm on rails 2.2.1 (eh, 2.2 RC2). Linux. SQlite.
Daniel B. (Guest)
on 2008-11-17 15:39
(Received via mailing list)
On Nov 17, 11:56 pm, sigvei <removed_email_address@domain.invalid> wrote:
> I have the following relationships:
>
> Document :has_many Proposals :has_many ProposalVersions.
>
> This fails:>> Document.first.proposals.first.proposal_versions.size

Do you mean Document.find(:first)...  ?

> ("proposal_versions".proposal_id = 2)
>
> I'm on rails 2.2.1 (eh, 2.2 RC2). Linux. SQlite.

-- Daniel B.
sigvei (Guest)
on 2008-11-17 16:20
(Received via mailing list)
On 17 Nov, 14:38, Daniel B. <removed_email_address@domain.invalid> wrote:
> On Nov 17, 11:56 pm, sigvei <removed_email_address@domain.invalid> wrote:
>
> > I have the following relationships:
>
> > Document :has_many Proposals :has_many ProposalVersions.
>
> > This fails:>> Document.first.proposals.first.proposal_versions.size
>
> Do you mean Document.find(:first)...  ?

ActiveRecord::Base::first is a convenience wrapper for
ActiveRecord::Base::find(:first), according to the API. So I can't
quite see why that should make a difference.
Frederick C. (Guest)
on 2008-11-17 16:37
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On 17 Nov 2008, at 14:19, sigvei wrote:

>> Do you mean Document.find(:first)...  ?
>
> ActiveRecord::Base::first is a convenience wrapper for
> ActiveRecord::Base::find(:first), according to the API. So I can't
> quite see why that should make a difference.

is there a document/proposal with id=2 (you've sort of implied that
there isn't, but I'm not quite sure)

Fred
Daniel B. (Guest)
on 2008-11-17 16:49
(Received via mailing list)
On Nov 18, 1:19 am, sigvei <removed_email_address@domain.invalid> wrote:
> > Do you mean Document.find(:first)...  ?
>
> ActiveRecord::Base::first is a convenience wrapper for
> ActiveRecord::Base::find(:first), according to the API. So I can't
> quite see why that should make a difference.

Sorry.  Wasn't familiar with it.  Hard to imagine rails putting in a
random id.
Can only surmise that
  Document.first.proposals.first.id==2
I don't think any order is guaranteed either unless you've
specified :order somewhere so it may change randomly depending on your
database.  Maybe you added a new proposal with no proposal versions in
addition to proposal with id=1.  Or a new document even.

--
Daniel B.
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