Rails - Aug 2006 - Transactions on Multiple Models

I can''t get transactions working correctly on multiple models.

I have an XML parser that''s importing a bunch of data into my system. I
have to update two different tables (models) but if anything at all
fails, I want it all rolled back. Here''s the code I''m using:

User.transaction do
  Field.transaction do
    user.update_attribute("blah", 1)
    field.update_attribute("other", 2)

    raise "test error"
  end
end

Unfortunately, the call to update_attribute on the User model commits
even though the call on the Field model does not. This code also fails:

User.transaction do
  user.update_attribute("blah", 1)

  Field.transaction do
    field.update_attribute("other", 2)

    raise "test error"
  end
end

Is there any way to do this such that ALL the DB calls will commit or
fail across multiple models?


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Hello,
I know that this will come across as ''flippant'', but, have you
actually
-read- the update_attribute description ?

Note: This method is overwritten by the Validation module that’ll make 
sure that updates made with this method doesn’t get subjected to 
validation checks. Hence, attributes can be updated even if the full 
object isn’t valid.

So, yes, from what -I- can see, update_attribute fires -instantly- and 
its not really to be used ''lightly''. Can I ask, whats wrong
with saying
user.blah = 1 and then field.other = 2 ? I also doubt that your database 
supports nested transactions, nor this is what you mean.

User.transaction do
user.blah = 1
field.other = 2

if field.save! and user.save! then
puts "everything hunky-dory"
end
end

No doubt, syntax isn''t precise, the moon isn''t in alignment or
some
other reason that this will probably be wrong, so ymmv, but hopefully 
you get the idea ;) Fyi, the save! will also auto-raise an error on 
failure, so, raising your own error isn''t required ;)

Regards
Stef

atraver-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
> I can''t get transactions working correctly on multiple models.
>
> I have an XML parser that''s importing a bunch of data into my
system. I
> have to update two different tables (models) but if anything at all
> fails, I want it all rolled back. Here''s the code I''m
using:
>
> User.transaction do
>   Field.transaction do
>     user.update_attribute("blah", 1)
>     field.update_attribute("other", 2)
>
>     raise "test error"
>   end
> end
>
> Unfortunately, the call to update_attribute on the User model commits
> even though the call on the Field model does not. This code also fails:
>
> User.transaction do
>   user.update_attribute("blah", 1)
>
>   Field.transaction do
>     field.update_attribute("other", 2)
>
>     raise "test error"
>   end
> end
>
> Is there any way to do this such that ALL the DB calls will commit or
> fail across multiple models?
>
>
> >
>
>   

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