diff options
Diffstat (limited to 'activerecord/lib/active_record/relation/finder_methods.rb')
| -rw-r--r-- | activerecord/lib/active_record/relation/finder_methods.rb | 134 |
1 files changed, 101 insertions, 33 deletions
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb index 435cef901b..0037398554 100644 --- a/activerecord/lib/active_record/relation/finder_methods.rb +++ b/activerecord/lib/active_record/relation/finder_methods.rb @@ -117,9 +117,9 @@ module ActiveRecord # def first(limit = nil) if limit - find_nth_with_limit(offset_index, limit) + find_nth_with_limit_and_offset(0, limit, offset: offset_index) else - find_nth(0, offset_index) + find_nth 0 end end @@ -145,15 +145,21 @@ module ActiveRecord # # [#<Person id:4>, #<Person id:3>, #<Person id:2>] def last(limit = nil) - if limit - if order_values.empty? && primary_key - order(arel_table[primary_key].desc).limit(limit).reverse - else - to_a.last(limit) - end - else - find_last - end + return find_last(limit) if loaded? || limit_value + + result = limit(limit || 1) + result.order!(arel_attribute(primary_key)) if order_values.empty? && primary_key + result = result.reverse_order! + + limit ? result.reverse : result.first + rescue ActiveRecord::IrreversibleOrderError + ActiveSupport::Deprecation.warn(<<-WARNING.squish) + Finding a last element by loading the relation when SQL ORDER + can not be reversed is deprecated. + Rails 5.1 will raise ActiveRecord::IrreversibleOrderError in this case. + Please call `to_a.last` if you still want to load the relation. + WARNING + find_last(limit) end # Same as #last but raises ActiveRecord::RecordNotFound if no record @@ -169,7 +175,7 @@ module ActiveRecord # Person.offset(3).second # returns the second object from OFFSET 3 (which is OFFSET 4) # Person.where(["user_name = :u", { u: user_name }]).second def second - find_nth(1, offset_index) + find_nth 1 end # Same as #second but raises ActiveRecord::RecordNotFound if no record @@ -185,7 +191,7 @@ module ActiveRecord # Person.offset(3).third # returns the third object from OFFSET 3 (which is OFFSET 5) # Person.where(["user_name = :u", { u: user_name }]).third def third - find_nth(2, offset_index) + find_nth 2 end # Same as #third but raises ActiveRecord::RecordNotFound if no record @@ -201,7 +207,7 @@ module ActiveRecord # Person.offset(3).fourth # returns the fourth object from OFFSET 3 (which is OFFSET 6) # Person.where(["user_name = :u", { u: user_name }]).fourth def fourth - find_nth(3, offset_index) + find_nth 3 end # Same as #fourth but raises ActiveRecord::RecordNotFound if no record @@ -217,7 +223,7 @@ module ActiveRecord # Person.offset(3).fifth # returns the fifth object from OFFSET 3 (which is OFFSET 7) # Person.where(["user_name = :u", { u: user_name }]).fifth def fifth - find_nth(4, offset_index) + find_nth 4 end # Same as #fifth but raises ActiveRecord::RecordNotFound if no record @@ -233,7 +239,7 @@ module ActiveRecord # Person.offset(3).forty_two # returns the forty-second object from OFFSET 3 (which is OFFSET 44) # Person.where(["user_name = :u", { u: user_name }]).forty_two def forty_two - find_nth(41, offset_index) + find_nth 41 end # Same as #forty_two but raises ActiveRecord::RecordNotFound if no record @@ -242,6 +248,38 @@ module ActiveRecord find_nth! 41 end + # Find the third-to-last record. + # If no order is defined it will order by primary key. + # + # Person.third_to_last # returns the third-to-last object fetched by SELECT * FROM people + # Person.offset(3).third_to_last # returns the third-to-last object from OFFSET 3 + # Person.where(["user_name = :u", { u: user_name }]).third_to_last + def third_to_last + find_nth(-3) + end + + # Same as #third_to_last but raises ActiveRecord::RecordNotFound if no record + # is found. + def third_to_last! + find_nth!(-3) + end + + # Find the second-to-last record. + # If no order is defined it will order by primary key. + # + # Person.second_to_last # returns the second-to-last object fetched by SELECT * FROM people + # Person.offset(3).second_to_last # returns the second-to-last object from OFFSET 3 + # Person.where(["user_name = :u", { u: user_name }]).second_to_last + def second_to_last + find_nth(-2) + end + + # Same as #second_to_last but raises ActiveRecord::RecordNotFound if no record + # is found. + def second_to_last! + find_nth!(-2) + end + # Returns true if a record exists in the table that matches the +id+ or # conditions given, or false otherwise. The argument can take six forms: # @@ -298,7 +336,7 @@ module ActiveRecord end # This method is called whenever no records are found with either a single - # id or multiple ids and raises a ActiveRecord::RecordNotFound exception. + # id or multiple ids and raises an ActiveRecord::RecordNotFound exception. # # The error message is different depending on whether a single id or # multiple ids are provided. If multiple ids are provided, then the number @@ -442,6 +480,8 @@ module ActiveRecord end def find_some(ids) + return find_some_ordered(ids) unless order_values.present? + result = where(primary_key => ids).to_a expected_size = @@ -463,49 +503,77 @@ module ActiveRecord end end + def find_some_ordered(ids) + ids = ids.slice(offset_value || 0, limit_value || ids.size) || [] + + result = except(:limit, :offset).where(primary_key => ids).records + + if result.size == ids.size + pk_type = @klass.type_for_attribute(primary_key) + + records_by_id = result.index_by(&:id) + ids.map { |id| records_by_id.fetch(pk_type.cast(id)) } + else + raise_record_not_found_exception!(ids, result.size, ids.size) + end + end + def find_take if loaded? @records.first else - @take ||= limit(1).to_a.first + @take ||= limit(1).records.first end end - def find_nth(index, offset) + def find_nth(index, offset = nil) + # TODO: once the offset argument is removed we rely on offset_index + # within find_nth_with_limit, rather than pass it in via + # find_nth_with_limit_and_offset + if offset + ActiveSupport::Deprecation.warn(<<-MSG.squish) + Passing an offset argument to find_nth is deprecated, + please use Relation#offset instead. + MSG + end if loaded? @records[index] else - offset += index - @offsets[offset] ||= find_nth_with_limit(offset, 1).first + offset ||= offset_index + @offsets[offset + index] ||= find_nth_with_limit_and_offset(index, 1, offset: offset).first end end def find_nth!(index) - find_nth(index, offset_index) or raise RecordNotFound.new("Couldn't find #{@klass.name} with [#{arel.where_sql(@klass.arel_engine)}]") + find_nth(index) or raise RecordNotFound.new("Couldn't find #{@klass.name} with [#{arel.where_sql(@klass.arel_engine)}]") end - def find_nth_with_limit(offset, limit) + def find_nth_with_limit(index, limit) + # TODO: once the offset argument is removed from find_nth, + # find_nth_with_limit_and_offset can be merged into this method relation = if order_values.empty? && primary_key - order(arel_table[primary_key].asc) + order(arel_attribute(primary_key).asc) else self end - relation = relation.offset(offset) unless offset.zero? + relation = relation.offset(index) unless index.zero? relation.limit(limit).to_a end - def find_last + private + + def find_nth_with_limit_and_offset(index, limit, offset:) # :nodoc: if loaded? - @records.last + @records[index, limit] else - @last ||= - if limit_value - to_a.last - else - reverse_order.limit(1).to_a.first - end + index += offset + find_nth_with_limit(index, limit) end end + + def find_last(limit) + limit ? records.last(limit) : records.last + end end end |