aboutsummaryrefslogtreecommitdiffstats
path: root/activerecord/lib/active_record/enum.rb
diff options
context:
space:
mode:
Diffstat (limited to 'activerecord/lib/active_record/enum.rb')
-rw-r--r--activerecord/lib/active_record/enum.rb26
1 files changed, 19 insertions, 7 deletions
diff --git a/activerecord/lib/active_record/enum.rb b/activerecord/lib/active_record/enum.rb
index 5fcc0382d8..837989aaa7 100644
--- a/activerecord/lib/active_record/enum.rb
+++ b/activerecord/lib/active_record/enum.rb
@@ -26,12 +26,23 @@ module ActiveRecord
#
# Good practice is to let the first declared status be the default.
#
- # Finally, it's also possible to explicitly map the relation between attribute and database integer:
+ # Finally, it's also possible to explicitly map the relation between attribute and
+ # database integer with a +Hash+:
#
# class Conversation < ActiveRecord::Base
# enum status: { active: 0, archived: 1 }
# end
#
+ # Note that when an +Array+ is used, the implicit mapping from the values to database
+ # integers is derived from the order the values appear in the array. In the example,
+ # <tt>:active</tt> is mapped to +0+ as it's the first element, and <tt>:archived</tt>
+ # is mapped to +1+. In general, the +i+-th element is mapped to <tt>i-1</tt> in the
+ # database.
+ #
+ # Therefore, once a value is added to the enum array, its position in the array must
+ # be maintained, and new values should only be added to the end of the array. To
+ # remove unused values, the explicit +Hash+ syntax should be used.
+ #
# In rare circumstances you might need to access the mapping directly.
# The mappings are exposed through a constant with the attributes name:
#
@@ -77,12 +88,13 @@ module ActiveRecord
end
end
- def _enum_methods_module
- @_enum_methods_module ||= begin
- mod = Module.new
- include mod
- mod
+ private
+ def _enum_methods_module
+ @_enum_methods_module ||= begin
+ mod = Module.new
+ include mod
+ mod
+ end
end
- end
end
end