diff options
| -rw-r--r-- | activerecord/lib/active_record/base.rb | 31 | ||||
| -rw-r--r-- | activerecord/lib/active_record/inheritance.rb | 31 |
2 files changed, 34 insertions, 28 deletions
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb index e93e4b6e3d..64cc5b68cc 100644 --- a/activerecord/lib/active_record/base.rb +++ b/activerecord/lib/active_record/base.rb @@ -220,34 +220,9 @@ module ActiveRecord #:nodoc: # # == Single table inheritance # - # Active Record allows inheritance by storing the name of the class in a column that by - # default is named "type" (can be changed by overwriting <tt>Base.inheritance_column</tt>). - # This means that an inheritance looking like this: - # - # class Company < ActiveRecord::Base; end - # class Firm < Company; end - # class Client < Company; end - # class PriorityClient < Client; end - # - # When you do <tt>Firm.create(name: "37signals")</tt>, this record will be saved in - # the companies table with type = "Firm". You can then fetch this row again using - # <tt>Company.where(name: '37signals').first</tt> and it will return a Firm object. - # - # Be aware that because the type column is an attribute on the record every new - # subclass will instantly be marked as dirty and the type column will be included - # in the list of changed attributes on the record. This is different from non - # STI classes: - # - # Company.new.changed? # => false - # Firm.new.changed? # => true - # Firm.new.changes # => {"type"=>["","Firm"]} - # - # If you don't have a type column defined in your table, single-table inheritance won't - # be triggered. In that case, it'll work just like normal subclasses with no special magic - # for differentiating between them or reloading the right type with find. - # - # Note, all the attributes for all the cases are kept in the same table. Read more: - # http://www.martinfowler.com/eaaCatalog/singleTableInheritance.html + # Active Record allows inheritance by storing the name of the class in a + # column that is named "type" by default. See ActiveRecord::Inheritance for + # more details. # # == Connection to multiple databases in different models # diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb index 08fc91c9df..5c2f1215d2 100644 --- a/activerecord/lib/active_record/inheritance.rb +++ b/activerecord/lib/active_record/inheritance.rb @@ -1,6 +1,37 @@ require 'active_support/core_ext/hash/indifferent_access' module ActiveRecord + # == Single table inheritance + # + # Active Record allows inheritance by storing the name of the class in a column that by + # default is named "type" (can be changed by overwriting <tt>Base.inheritance_column</tt>). + # This means that an inheritance looking like this: + # + # class Company < ActiveRecord::Base; end + # class Firm < Company; end + # class Client < Company; end + # class PriorityClient < Client; end + # + # When you do <tt>Firm.create(name: "37signals")</tt>, this record will be saved in + # the companies table with type = "Firm". You can then fetch this row again using + # <tt>Company.where(name: '37signals').first</tt> and it will return a Firm object. + # + # Be aware that because the type column is an attribute on the record every new + # subclass will instantly be marked as dirty and the type column will be included + # in the list of changed attributes on the record. This is different from non + # STI classes: + # + # Company.new.changed? # => false + # Firm.new.changed? # => true + # Firm.new.changes # => {"type"=>["","Firm"]} + # + # If you don't have a type column defined in your table, single-table inheritance won't + # be triggered. In that case, it'll work just like normal subclasses with no special magic + # for differentiating between them or reloading the right type with find. + # + # Note, all the attributes for all the cases are kept in the same table. Read more: + # http://www.martinfowler.com/eaaCatalog/singleTableInheritance.html + # module Inheritance extend ActiveSupport::Concern |