# Validates uniqueness scope

**URL:** <https://discuss.rubyonrails.org/t/validates-uniqueness-scope/50282>\
**Category:** rubyonrails-talk\
**Created:** [March 21, 2010, 4:23am UTC](https://discuss.rubyonrails.org/t/validates-uniqueness-scope/50282 "2010-03-21T04:23:34Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Angelo\_Ashmore](https://avatars.discourse-cdn.com/v4/letter/a/82dd89/32.png) [@Angelo\_Ashmore](https://discuss.rubyonrails.org/u/Angelo_Ashmore)\
**Post date:** [March 21, 2010, 4:23am UTC](https://discuss.rubyonrails.org/t/validates-uniqueness-scope/50282/1 "2010-03-21T04:23:34Z")

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In a Rails 2.x validation to check if the name of some model is unique within a some category, I would use:

`validates_uniqueness_of :name, :scope =\> :category_id`

In Rails 3, this is replaced with:

`validates :name, :uniqueness =\> true`

However, I can't seem to find a method of defining the uniqueness' scope. Am I missing something?

Thanks, Angelo