instance method interpolate_sanitized_sql

# File activerecord/lib/active_record/base.rb, line 1749
      def interpolate_sanitized_sql(sanitized, record = nil, sanitize_klass = self.class)
        if sanitized =~ /\#\{.*\}/
          ActiveSupport::Deprecation.warn(
            'String-based interpolation of association conditions is deprecated. Please use a ' \
            'proc instead. So, for example, has_many :older_friends, :conditions => \'age > #{age}\' ' \
            'should be changed to has_many :older_friends, :conditions => proc { "age > #{age}" }.'
          )
          instance_eval("%@#{sanitized.gsub('@', '\@')}@", __FILE__, __LINE__)
        elsif sanitized.respond_to?(:to_proc)
          sanitize_klass.send(:sanitize_sql, instance_exec(record, &sanitized))
        else
          sanitized
        end
      end