Class ActiveRecord::Validations::UniquenessValidator < ActiveModel::EachValidator

   # File activerecord/lib/active_record/validations/uniqueness.rb, line 6
6:       def initialize(options)
7:         super(options.reverse_merge(:case_sensitive => true))
8:       end

    # File activerecord/lib/active_record/validations/uniqueness.rb, line 11
11:       def setup(klass)
12:         @klass = klass
13:       end

    # File activerecord/lib/active_record/validations/uniqueness.rb, line 15
15:       def validate_each(record, attribute, value)
16:         finder_class = find_finder_class_for(record)
17:         table = finder_class.arel_table
18: 
19:         coder = record.class.serialized_attributes[attribute.to_s]
20: 
21:         if value && coder
22:           value = coder.dump value
23:         end
24: 
25:         relation = build_relation(finder_class, table, attribute, value)
26:         relation = relation.and(table[finder_class.primary_key.to_sym].not_eq(record.send(:id))) if record.persisted?
27: 
28:         Array.wrap(options[:scope]).each do |scope_item|
29:           scope_value = record.send(scope_item)
30:           relation = relation.and(table[scope_item].eq(scope_value))
31:         end
32: 
33:         if finder_class.unscoped.where(relation).exists?
34:           record.errors.add(attribute, :taken, options.except(:case_sensitive, :scope).merge(:value => value))
35:         end
36:       end