I have an ActiveRecord transaction that works some times and fails some
times. I''ve narrowed it down to where the failure depends on the
inclusion of an empty method from a library object. By
''empty'', I mean
I''ve removed all code from the method, so the problem is related to
making the method call (i.e. it''s not in my code). Here''s some
pseudo
code.
def myMethod
ClassA.transaction do
# saving class B obj succeeds when this next method is commented
out,
# but it fails with ''update violates foreign key
constraint'' when
this method is called
MyLibraryClass.donothing
@objectOfClassA.save!
@objectOfClassB.refToA = objectOfClassA.id
@objectOfClassB.save!
end
end
It behaves as if the second save cannot see the object created in the
first save, even though they both happen within the transaction.
Why would the inclusion of the unrelated, empty method
''donothing'' have
such an effect?
--
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Frederick Cheung
2008-Apr-30 19:06 UTC
Re: weird foreign key constraint failure in transaction
On 30 Apr 2008, at 19:45, Seth Tager wrote:> > I have an ActiveRecord transaction that works some times and fails > some > times. I''ve narrowed it down to where the failure depends on the > inclusion of an empty method from a library object. By ''empty'', I mean > I''ve removed all code from the method, so the problem is related to > making the method call (i.e. it''s not in my code). Here''s some pseudo > code. > > def myMethod > ClassA.transaction do > # saving class B obj succeeds when this next method is commented > out, > # but it fails with ''update violates foreign key constraint'' when > this method is called > MyLibraryClass.donothing > @objectOfClassA.save! > @objectOfClassB.refToA = objectOfClassA.idI assume this should read @objectOfClassB.refToA = @objectOfClassA.id> > @objectOfClassB.save! > end > end > > It behaves as if the second save cannot see the object created in the > first save, even though they both happen within the transaction. > > Why would the inclusion of the unrelated, empty method ''donothing'' > have > such an effect?Because saying MyLibraryClass means const_missing is hit, triggering the load of my_library_class.rb which contains something funny? (if true then just putting MyLibraryClass in your method (ie call no method on it at all) will also trigger the error you are seeing). Fred --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Frederick Cheung wrote:> On 30 Apr 2008, at 19:45, Seth Tager wrote: > >> ClassA.transaction do >> # saving class B obj succeeds when this next method is commented >> out, >> # but it fails with ''update violates foreign key constraint'' when >> this method is called >> MyLibraryClass.donothing >> @objectOfClassA.save! >> @objectOfClassB.refToA = objectOfClassA.id > I assume this should read @objectOfClassB.refToA = @objectOfClassA.idyes, that''s how it should have read.>> such an effect? > Because saying MyLibraryClass means const_missing is hit, triggering > the load of my_library_class.rb which contains something funny? (if > true then just putting > MyLibraryClass in your method (ie call no method on it at all) will > also trigger the error you are seeing).You''re correct. The error is triggered even with no method call. But even weirder, I moved the MyLibraryClass statement outside of the transaction entirely and it still triggered the error. However, your message helped: you got me wondering what was in the library class and I found that another developer had added this: require File.dirname(__FILE__) + ''/../config/environment'' and that turns out to be causing a problem. I can''t explain why that would cause the observed behavior, but at least it''s fixed. Thanks. -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---