From 6185c4947e88f1b6b7c2adaabf62081bac6df04a Mon Sep 17 00:00:00 2001
From: Mattias Pfeiffer <mattias@pfeiffer.dk>
Date: Wed, 7 Mar 2012 12:51:43 +0100
Subject: Add :conditions option to uniqueness validator

---
 activerecord/lib/active_record/validations/uniqueness.rb | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

(limited to 'activerecord/lib/active_record/validations')

diff --git a/activerecord/lib/active_record/validations/uniqueness.rb b/activerecord/lib/active_record/validations/uniqueness.rb
index 9556878f63..eb3a34c4cc 100644
--- a/activerecord/lib/active_record/validations/uniqueness.rb
+++ b/activerecord/lib/active_record/validations/uniqueness.rb
@@ -35,8 +35,8 @@ module ActiveRecord
           relation = relation.and(table[scope_item].eq(scope_value))
         end
 
-        if finder_class.unscoped.where(relation).exists?
-          record.errors.add(attribute, :taken, options.except(:case_sensitive, :scope).merge(:value => value))
+        if finder_class.unscoped.where(relation).where(options[:conditions]).exists?
+          record.errors.add(attribute, :taken, options.except(:case_sensitive, :scope, :conditions).merge(:value => value))
         end
       end
 
@@ -102,6 +102,14 @@ module ActiveRecord
       #     validates_uniqueness_of :teacher_id, :scope => [:semester_id, :class_id]
       #   end
       #
+      # It is also possible to limit the uniqueness constraint to a set of records matching certain conditions.
+      # In this example archived articles with are not being taken into consideration when validating uniqueness
+      # of the title attribute:
+      #
+      #   class Article < ActiveRecord::Base
+      #     validates_uniqueness_of :title, :conditions => ['status != ?', 'archived']
+      #   end
+      #
       # When the record is created, a check is performed to make sure that no record exists in the database
       # with the given value for the specified attribute (that maps to a column). When the record is updated,
       # the same check is made but disregarding the record itself.
@@ -109,6 +117,8 @@ module ActiveRecord
       # Configuration options:
       # * <tt>:message</tt> - Specifies a custom error message (default is: "has already been taken").
       # * <tt>:scope</tt> - One or more columns by which to limit the scope of the uniqueness constraint.
+      # * <tt>:conditions</tt> - Specify the conditions to be included as a <tt>WHERE</tt> SQL fragment to limit
+      #   the uniqueness constraint lookup. (e.g. <tt>:conditions => {:status => 'active'}</tt>)
       # * <tt>:case_sensitive</tt> - Looks for an exact match. Ignored by non-text columns (+true+ by default).
       # * <tt>:allow_nil</tt> - If set to true, skips this validation if the attribute is +nil+ (default is +false+).
       # * <tt>:allow_blank</tt> - If set to true, skips this validation if the attribute is blank (default is +false+).
-- 
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