# :dependent for not destroying **URL:** \ **Category:** Rails\ **Created:** [December 30, 2007, 11:34am UTC](https://www.ruby-forum.com/t/dependent-for-not-destroying/124571 "2007-12-30T11:34:04Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![rpflaum](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/d2c977/32.png) [@rpflaum](https://www.ruby-forum.com/u/rpflaum)\ **Post date:** [December 30, 2007, 11:34am UTC](https://www.ruby-forum.com/t/dependent-for-not-destroying/124571/1 "2007-12-30T11:34:04Z")
Hi, Is there a way to use the :dependent option to set a certain attribute to null rather than destroying the records? For example, take the following models: User id, integer name, string group\_id, integer belongs\_to :democrats Groups id, integer name, string has\_many :users If I delete a certain group, is there a way to have the ‘group\_id’ attribute of all the users affiliated with the deleted group be set to null rather than be destroyed? Thank you! ---
**Author:** ![rpflaum](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/d2c977/32.png) [@rpflaum](https://www.ruby-forum.com/u/rpflaum)\ **Post date:** [December 30, 2007, 12:09pm UTC](https://www.ruby-forum.com/t/dependent-for-not-destroying/124571/2 "2007-12-30T12:09:41Z")
Ooooh, I’m so excited. I found my answer. :dependent =\> :nullify will do what I want. I hope this will help some person in the future. ---
**Author:** ![rpflaum](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/d2c977/32.png) [@rpflaum](https://www.ruby-forum.com/u/rpflaum)\ **Post date:** [December 31, 2007, 2:41am UTC](https://www.ruby-forum.com/t/dependent-for-not-destroying/124571/3 "2007-12-31T02:41:05Z")
No it doesn’t. You’ll need to build your own before\_destroy validation method for this. ---
**Author:** ![rpflaum](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/d2c977/32.png) [@rpflaum](https://www.ruby-forum.com/u/rpflaum)\ **Post date:** [December 31, 2007, 2:35am UTC](https://www.ruby-forum.com/t/dependent-for-not-destroying/124571/4 "2007-12-31T02:35:50Z")
Now if there was just a built-in way to have something like :dependent =\> :deny we’d be set. By the way, what is the best way to support the “deny delete” association rule. Just to clarify this is saying “Deny deletion of the parent object if it has one or more children.” This rule is often useful to ensure referential integrity. Example: Scenario 1: An admin creates a new product with item number 1010. It is realized later that the item will never be sold. Since no orders of the product exist in the system it’s fine to delete the item. Scenario 2: It is discovered that an existing product with item number 1001 is no longer available to be sold. The admin attempts to delete the existing product, but there are outstanding orders containing product 1001. It’s not good to use either :dependent =\> :destroy nor :dependent =\> :nullify in this scenario. You can’t simply let the system automatically delete all orders containing product 1001. You must first resolve the orders (child objects) before deleting the product object. Does Rails have built-in support for this common referential integrity rule? On Dec 30, 6:09 am, Rick P. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![rpflaum](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/d2c977/32.png) [@rpflaum](https://www.ruby-forum.com/u/rpflaum)\ **Post date:** [December 31, 2007, 11:58am UTC](https://www.ruby-forum.com/t/dependent-for-not-destroying/124571/5 "2007-12-31T11:58:07Z")
If I understood you correctly I think this plugins does what you want. [http://agilewebdevelopment.com/plugins/dependent\_protect\_option](http://agilewebdevelopment.com/plugins/dependent_protect_option) – Amaia C. Dabne Tecnologías de la Información - [www.dabne.net](http://www.dabne.net) - [http://blog.dabne.net](http://blog.dabne.net) ~~\*~~ Buscador de Subvenciones - [http://buscaboe.dabne.net](http://buscaboe.dabne.net) ~~\*~~ 2007/12/31, Robert W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):