Rodrigo,
This approach seems very interesting but I have one question.
What you do if user create a company and do not fill the partners (i.e.: go to
other screen before filling the partners) and use that company on the system?
On Aug 5, 2012, at 1:07 PM, Rodrigo Rosenfeld Rosas wrote:
> In that case I'd handle errors like this in the client-side level besides the
> database level since I find it simpler, specially if you're using an OO
> approach with your models isolated from your views.
>
> In that case, if there is a bug in your client-side code that will send
> duplicate entries to the server, in the worst case you'll get a 500 response
> if you don't handle it in the server.
>
> Another approach if you want to handle this in the server-side would be to do
> something like this:
>
> begin
> start_database_transaction
> company = Company.create! params[:company] # simplified here, just create
> the company with minimal params
> # then add the partners to the company and ask to validate company. Now the
> partners should have a valid company_id and the built-in validations should
> work
> ...
> unless company.valid?
> handle_validation_error company.errors
> raise 'duplicate entries'
> end
> ...
> rescue
> rollback_database_transaction
> end
>
> Of course the suggestion above would only work with serious databases (ie,
> not with the MyISAM engine in MySql, which is the default for older versions
> of MySql).
>
> In any case I'd suggest to release your gem first and then ask here if the
> Rails core would be willing to include it by default in ActiveRecord. In that
> case they would be able to look at the documentation, source code and tests
> before making a decision.
>
> But I'd like to tell you why I think lots of people are not using nested
> params. If they're like me the work-flow would look something like this:
>
> The user clicks in a Add Company button and would be asked the company name.
> The application creates the company with no partners associated.
>
> Then the interface would add a button "Add partner" asking for the partner
> data. In that case your actions would have to deal with a single partner at
> once, making it easier to work with regular validations and simplifying the
> logic too.
>
> What I mean is that I find it quite easier to develop applications using AJAX
> than trying to create complex forms that do lots of stuff in a single
> request. Even testing such forms are painful in my opinion. It is much easier
> to split the application in multiple small parts that are easily testable
> separately.
>
> Good luck with your decisions,
>
> Rodrigo.
>
>
> Em 05-08-2012 12:42, Gabriel Sobrinho escreveu:
>>
>> Rodrigo,
>>
>> I'm doing that at database level but I'm not handling the exception because
>> it happens very infrequently.
>>
>> The point is the validation message that I have to show like any others
>> validations.
>>
>>
>> Another problem is that I have more than one case like this per form.
>>
>> I used the partner case but in this same form I have another nested called
>> company activities that can't repeat the CNAE (an activity means initial
>> date, final date and CNAE).
>>
>> In this form I have 2 "in-memory" validations but I have others that have
>> more than 5 nested like this.
>>
>>
>> It will be very painfully if I have to handle each exception to discover
>> what nested failed and add the error by hand.
>>
>>
>> Like I said before, I see this problem happening over and over again in
>> systems I've worked.
>>
>> But that can be an "enterprise" feature that does not fit to active record
>> proposal.
>>
>>
>> In that case, I will keep it as a separated gem.
>>
>> I just want to be sure if I should submit a PR or something like that :)
>>
>> On Aug 5, 2012, at 12:26 PM, Rodrigo Rosenfeld Rosas wrote:
>>
>>> That is why constraints should be handled by databases in my opinion.
>>>
>>> Just create the unique index in the database and write something like this:
>>>
>>> begin
>>> company.save!
>>> rescue UniqueConstraintException => e # I don't really know the name for
>>> this exception
>>> render json: {error_message: "Please remove the duplicate entries."}
>>> rescue e # general rescuer
>>> log.error "Couldn't create company", e # not sure if that is the right
>>> syntax
>>> render json: {error_message: "We could't process your request. Please
>>> contact our support team."}
>>> end
>>>
>>> Well, at least this has always been my opinion and the reason why I prefer
>>> writing validations in the database using unique constraints or triggers.
>>>
>>> Usually the ActiveRecord and Hibernate communities among others don't
>>> recommend this approach if you intend to support multiple databases, but
>>> since I always use PostgreSQL, this is not an issue to me. That is one of
>>> the reasons I prefer Sequel over AR. The Sequel community
>>> will usually prefer handling validations in the database-level even though
>>> you can use validators in Ruby as well to make it easy to handle simple
>>> cases but you should always replicate the validations in the database level
>>> as well.
>>>
>>> Well, that is my opinion since you asked :)
>>>
>>> Cheers,
>>> Rodrigo.
>>>
>>> Em 05-08-2012 11:36, Gabriel Sobrinho escreveu:
>>>>
>>>> Anyone have some opinion?
>>>>
>>>> On Sunday, July 29, 2012 4:17:01 PM UTC-3, Gabriel Sobrinho wrote:
>>>> Hi,
>>>>
>>>> Currently uniqueness validator uses database queries which not work for
>>>> nested forms.
>>>>
>>>>
>>>> For example, I have a company form which have many partners and each
>>>> partner have a person and a percentage.
>>>>
>>>> Using uniqueness validator, I can not guarantee someone will not be a
>>>> partner two times because the partners aren't on database yet.
>>>>
>>>>
>>>> We've implemented a validator similar to this one:
>>>> http://pastie.org/private/osa3pmono5l1ykrd7vipwa
>>>>
>>>>
>>>> I'm not sure if the uniqueness validator should handle it.
>>>>
>>>> Take a look: http://pastie.org/private/maxdpn4gmvftzcl2ka0mq
>>>>
>>>>
>>>> I'm not sure if it will be too complex to the proposal of uniqueness
>>>> validator but that is a common validation for each system I've worked in
>>>> last years.
>>>>
>>>> WDYT? Something like that should be on the active record or a gem?
>>>>
>>>> Cheers,
>>>>
>>>> Gabriel Sobrinho
>>>> gabrielsobrinho.com
>>>>
>>>>
>>>
>>>
>
>
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Cheers,
Gabriel Sobrinho
gabrielsobrinho.com
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