find_by

# File activerecord/lib/active_record/core.rb, line 287
      def find_by(*args) # :nodoc:
        return super if scope_attributes?

        hash = args.first
        return super unless Hash === hash

        hash = hash.each_with_object({}) do |(key, value), h|
          key = key.to_s
          key = attribute_aliases[key] || key

          return super if reflect_on_aggregation(key)

          reflection = _reflect_on_association(key)

          if !reflection
            value = value.id if value.respond_to?(:id)
          elsif reflection.belongs_to? && !reflection.polymorphic?
            key = reflection.join_foreign_key
            pkey = reflection.join_primary_key
            value = value.public_send(pkey) if value.respond_to?(pkey)
          end

          if !columns_hash.key?(key) || StatementCache.unsupported_value?(value)
            return super
          end

          h[key] = value
        end

        keys = hash.keys
        statement = cached_find_by_statement(keys) { |params|
          wheres = keys.index_with { params.bind }
          where(wheres).limit(1)
        }

        begin
          statement.execute(hash.values, connection).first
        rescue TypeError
          raise ActiveRecord::StatementInvalid
        end
      end