Docfixes (closes #11356, #11172, #10523)

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@9064 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 3 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index d8332249fb..d7d5d9b312 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -809,6 +809,8 @@ module ActiveRecord
       #   destroyed. This requires that a column named <tt>#{table_name}_count</tt> (such as +comments_count+ for a belonging +Comment+ class)
       #   is used on the associate class (such as a +Post+ class). You can also specify a custom counter cache column by providing
       #   a column name instead of a +true+/+false+ value to this option (e.g., <tt>:counter_cache => :my_custom_counter</tt>.)
+      #   When creating a counter cache column, the database statement or migration must specify a default value of <tt>0</tt>, failing to do 
+      #   this results in a counter with NULL value, which will never increment.
       #   Note: Specifying a counter_cache will add it to that model's list of readonly attributes using #attr_readonly.
       # * <tt>:include</tt>  - specify second-order associations that should be eager loaded when this object is loaded.
       #   Not allowed if the association is polymorphic.
@@ -824,6 +826,7 @@ module ActiveRecord
       #              :conditions => 'discounts > #{payments_count}'
       #   belongs_to :attachable, :polymorphic => true
       #   belongs_to :project, :readonly => true
+      #   belongs_to :post, :counter_cache => true
       def belongs_to(association_id, options = {})
         reflection = create_belongs_to_reflection(association_id, options)