Added some more documentation for ActiveRecord::Associations::Builder::Association class

1 files changed, 11 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/associations/builder/association.rb b/activerecord/lib/active_record/associations/builder/association.rb
index 34684fd71a..456041cce8 100644
--- a/activerecord/lib/active_record/associations/builder/association.rb
+++ b/activerecord/lib/active_record/associations/builder/association.rb
@@ -1,6 +1,17 @@
 # This is the parent Association class which defines certain class variables (valid_options) and
 # instance variables (model, name, scope, options, reflection) which would be common across all the associations that we known today in Rails..
 # Every association need to have the values of these variables set and they are used at multiple places
+# The heirarchy is defined as follows:
+#  Association 
+#    - SingularAssociation
+#      - BelongsTo
+#      - HasOne
+#    - CollectionAssociation
+#      - HasMany
+#      - HasAndBelongsToMany
+#
+# The HasMany :Through association is a special case of HasMany association with the :through option set for it
+#
 
 module ActiveRecord::Associations::Builder
   class Association #:nodoc: