# Selective validation? Is it possible? **URL:** \ **Category:** Rails\ **Created:** [October 29, 2006, 9:54am UTC](https://www.ruby-forum.com/t/selective-validation-is-it-possible/74032 "2006-10-29T09:54:37Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Petr](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ac8455/32.png) [@Petr](https://www.ruby-forum.com/u/Petr)\ **Post date:** [October 29, 2006, 9:54am UTC](https://www.ruby-forum.com/t/selective-validation-is-it-possible/74032/1 "2006-10-29T09:54:37Z")
I have a Product model and products table. Im using acts\_as\_tree structure. I would like active record validation to be done on children only. Anyway to do this? Petr ---
**Author:** ![Petr](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ac8455/32.png) [@Petr](https://www.ruby-forum.com/u/Petr)\ **Post date:** [October 29, 2006, 11:34am UTC](https://www.ruby-forum.com/t/selective-validation-is-it-possible/74032/2 "2006-10-29T11:34:40Z")
Hello Petr, > I have a Product model and products table. Im using acts\_as\_tree > structure. I would like active record validation to be done on children > only. Anyway to do this? The root product is the product who has no parent. So in your validation, you could pass an :if option and a condition in the block : :if =\> Proc.new { |r| r.parent } Example : validates\_presence\_of :name, :if =\> Proc.new { |r| r.parent } – Jean-François. – Ã? la renverse. ---
**Author:** ![Petr](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ac8455/32.png) [@Petr](https://www.ruby-forum.com/u/Petr)\ **Post date:** [October 29, 2006, 11:56am UTC](https://www.ruby-forum.com/t/selective-validation-is-it-possible/74032/3 "2006-10-29T11:56:41Z")
Hello Petr, I think this can be done. Here provided an example were a validation runs only for certain customer types. validates\_presence\_of :birthday, :street, :street\_number, :zip\_code, :city, :bank\_name, :bank\_code, :bank\_account, :telefon\_number, :message =\> “darf nicht leer sein.”, :if =\> Proc.new { | customer | customer.customer\_type.name == “partner” or customer.customer\_type.name == “customer” } The important part for you is the :if part. Only for object that pass the test in the Proc the validation is used. There is a “has\_parent?” method for act\_as\_tree objects. I think this could be used for your problem… Feurio ---
**Author:** ![Petr](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ac8455/32.png) [@Petr](https://www.ruby-forum.com/u/Petr)\ **Post date:** [October 29, 2006, 12:02pm UTC](https://www.ruby-forum.com/t/selective-validation-is-it-possible/74032/4 "2006-10-29T12:02:58Z")
Hey, thanks. I have one more question, could you describe to me what that does in detail? I know Proc objects from Ruby, I just cant imagine how it works in this case. Petr Jean-François wrote: > Hello Petr, > > > I have a Product model and products table. Im using acts\_as\_tree > > structure. I would like active record validation to be done on children > > only. Anyway to do this? > > The root product is the product who has no parent. > So in your validation, you could pass an :if option and a condition > in the block : > > :if =\> Proc.new { |r| r.parent } > > Example : > validates\_presence\_of :name, :if =\> Proc.new { |r| r.parent } > > – Jean-François. > > – > Ã? la renverse. ---
**Author:** ![Petr](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ac8455/32.png) [@Petr](https://www.ruby-forum.com/u/Petr)\ **Post date:** [October 29, 2006, 12:06pm UTC](https://www.ruby-forum.com/t/selective-validation-is-it-possible/74032/5 "2006-10-29T12:06:08Z")
Nevermind, I figured it out. 🙂 Thanks a lot! Petr Petr wrote: > Hey, thanks. I have one more question, could you describe to me what > that does in detail? I know Proc objects from Ruby, I just cant imagine > how it works in this case. > > Petr > > Jean-François wrote: > > > Hello Petr, > > > > > I have a Product model and products table. Im using acts\_as\_tree > > > structure. I would like active record validation to be done on children > > > only. Anyway to do this? > > > > The root product is the product who has no parent. > > So in your validation, you could pass an :if option and a condition > > in the block : > > > > :if =\> Proc.new { |r| r.parent } > > > > Example : > > validates\_presence\_of :name, :if =\> Proc.new { |r| r.parent } > > > > – Jean-François. > > > > – > > Ã? la renverse. ---
**Author:** ![Petr](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ac8455/32.png) [@Petr](https://www.ruby-forum.com/u/Petr)\ **Post date:** [October 29, 2006, 12:16pm UTC](https://www.ruby-forum.com/t/selective-validation-is-it-possible/74032/6 "2006-10-29T12:16:41Z")
Hello Feurio, > There is a “has\_parent?” method for act\_as\_tree objects. I think this > could be used for your problem… acts\_as\_tree defines a belongs\_to association named ‘parent’, so you can benefit from a #has\_parent? method. However this method is deprecated and you should use #parent (that is, the method with the name of the association), if there is no associated record, it returns nil then in a condition it will be false so you can use it. Note that if you have a has\_many :foos association, #has\_foos? is also deprecated. – Jean-François. – Ã? la renverse.