Rails - Jan 2005 - rolling back transactions based on validation errors

Does anybody have a case where you are validating multiple activerecord objects
in a single request, and you want all of them to be validated, and you want all
of them stored in the database, but not if any of them fail at validation? I was
going over possible ways to do this, and I thought it might be a nice feature to
include in the framework. Maybe a block method to put your code in that throws
an exception if there are any validation errors (after processing everything in
the block), or that keeps a boolean "is_valid" locally, and that way
the transaction block could be optional.

I''d appreciate any input.

-Jeff

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Maybe something like this: 

if @request.post? and @record1.valid? and @record2.valid? 
   Any.transaction do 
     @record1.save or raise "?!" 
     @record2.save or raise "?!"
  end
end


On Fri, 21 Jan 2005 15:42:37 -0700, Jeffrey Moss
<jeff-61uStg5MtoFWk0Htik3J/w@public.gmane.org>
wrote:
>  
> Does anybody have a case where you are validating multiple activerecord
> objects in a single request, and you want all of them to be validated, and
> you want all of them stored in the database, but not if any of them fail at
> validation? I was going over possible ways to do this, and I thought it
> might be a nice feature to include in the framework. Maybe a block method
to
> put your code in that throws an exception if there are any validation
errors
> (after processing everything in the block), or that keeps a boolean
> "is_valid" locally, and that way the transaction block could be
optional.
>   
> I''d appreciate any input. 
>   
> -Jeff 
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
> 
> 
> 

-- 
Tobi
http://www.hieraki.org   - Open source book authoring
http://blog.leetsoft.com - Technical weblog

What is the "Any" class?


On Sun, 23 Jan 2005 10:21:46 -0500, Tobias Luetke
<tobias.luetke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> Maybe something like this:
> 
> if @request.post? and @record1.valid? and @record2.valid?
>    Any.transaction do
>      @record1.save or raise "?!"
>      @record2.save or raise "?!"
>   end
> end
> 
> 
> On Fri, 21 Jan 2005 15:42:37 -0700, Jeffrey Moss
<jeff-61uStg5MtoFWk0Htik3J/w@public.gmane.org> wrote:
> >
> > Does anybody have a case where you are validating multiple
activerecord
> > objects in a single request, and you want all of them to be validated,
and
> > you want all of them stored in the database, but not if any of them
fail at
> > validation? I was going over possible ways to do this, and I thought
it
> > might be a nice feature to include in the framework. Maybe a block
method to
> > put your code in that throws an exception if there are any validation
errors
> > (after processing everything in the block), or that keeps a boolean
> > "is_valid" locally, and that way the transaction block could
be optional.
> >
> > I''d appreciate any input.
> >
> > -Jeff 
> > _______________________________________________
> > Rails mailing list
> > Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
> >
> >
> >
> 
> --
> Tobi
> http://www.hieraki.org   - Open source book authoring
> http://blog.leetsoft.com - Technical weblog
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

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Duane Johnson wrote:
> What is the "Any" class?
It''s something like the "any" key on your keyboard ;)  Every
model class
has a transaction class method that begins, possibly rolls back, and
commits a transaction on its database connection.  Pseudocode:

def transaction
  @connection.begin_transaction
  result = yield
  @connection.commit_transaction
  return result
rescue Exception
  @connection.rollback_transaction
  raise
end

Additionally, every model has a transaction instance method which calls
self.class.transaction; thus, you may use transactions with "Any"
model
class or instance.

jeremy
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This is essentially what I did, but this calls valid twice, once in the
conditional and then again when you save (correct me if I''m wrong, I
glanced through the libraries). In order to prevent validation being
called twice though, I just use the transaction to roll back if there is a
validation failure. Something like this:

if @request.post?
  all_valid = TRUE;
  Any.transaction do
    all_valid = FALSE unless @record1.save


> Maybe something like this:
>
> if @request.post? and @record1.valid? and @record2.valid?
>    Any.transaction do
>      @record1.save or raise "?!"
>      @record2.save or raise "?!"
>   end
> end
>
>
> On Fri, 21 Jan 2005 15:42:37 -0700, Jeffrey Moss
<jeff-61uStg5MtoFWk0Htik3J/w@public.gmane.org>
> wrote:
>>
>> Does anybody have a case where you are validating multiple activerecord
>> objects in a single request, and you want all of them to be validated,
>> and
>> you want all of them stored in the database, but not if any of them
fail
>> at
>> validation? I was going over possible ways to do this, and I thought it
>> might be a nice feature to include in the framework. Maybe a block
>> method to
>> put your code in that throws an exception if there are any validation
>> errors
>> (after processing everything in the block), or that keeps a boolean
>> "is_valid" locally, and that way the transaction block could
be
>> optional.
>>
>> I''d appreciate any input.
>>
>> -Jeff
>> _______________________________________________
>> Rails mailing list
>> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
>> http://lists.rubyonrails.org/mailman/listinfo/rails
>>
>>
>>
>
>
> --
> Tobi
> http://www.hieraki.org   - Open source book authoring
> http://blog.leetsoft.com - Technical weblog
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

This is essentially what I did, but this calls valid twice, once in the
conditional and then again when you save (correct me if I''m wrong, I
glanced through the libraries). In order to prevent validation being
called twice though, I just use the transaction to roll back if there is a
validation failure. Something like this:

if @request.post?
  all_valid = TRUE;
  Any.transaction do
    all_valid = FALSE unless @record1.save
    all_valid = FALSE unless @record2.save
    raise "error" unless all_valid
  end
end

but what would be really cool is if you could do somehting like this:

if @request.post?
  Any.transaction(:validate_all => :yes) do
    @record1.save
    @record2.save
  end
end

And that would raise the exception after everything in the block had been
processed and there were validation errors.

P.S. Please excuse my incomplete post.

-Jeff
> Maybe something like this:
>
> if @request.post? and @record1.valid? and @record2.valid?
>    Any.transaction do
>      @record1.save or raise "?!"
>      @record2.save or raise "?!"
>   end
> end
>
>
> On Fri, 21 Jan 2005 15:42:37 -0700, Jeffrey Moss
<jeff-61uStg5MtoFWk0Htik3J/w@public.gmane.org>
> wrote:
>>
>> Does anybody have a case where you are validating multiple activerecord
>> objects in a single request, and you want all of them to be validated,
>> and
>> you want all of them stored in the database, but not if any of them
fail
>> at
>> validation? I was going over possible ways to do this, and I thought it
>> might be a nice feature to include in the framework. Maybe a block
>> method to
>> put your code in that throws an exception if there are any validation
>> errors
>> (after processing everything in the block), or that keeps a boolean
>> "is_valid" locally, and that way the transaction block could
be
>> optional.
>>
>> I''d appreciate any input.
>>
>> -Jeff
>> _______________________________________________
>> Rails mailing list
>> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
>> http://lists.rubyonrails.org/mailman/listinfo/rails
>>
>>
>>
>
>
> --
> Tobi
> http://www.hieraki.org   - Open source book authoring
> http://blog.leetsoft.com - Technical weblog
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>