diff options
| -rw-r--r-- | guides/source/association_basics.md | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/guides/source/association_basics.md b/guides/source/association_basics.md index ec6017ff73..58cff01a10 100644 --- a/guides/source/association_basics.md +++ b/guides/source/association_basics.md @@ -875,18 +875,26 @@ end With this declaration, Rails will keep the cache value up to date, and then return that value in response to the `size` method. -Although the `:counter_cache` option is specified on the model that includes the `belongs_to` declaration, the actual column must be added to the _associated_ model. In the case above, you would need to add a column named `orders_count` to the `Customer` model. You can override the default column name if you need to: +Although the `:counter_cache` option is specified on the model that includes +the `belongs_to` declaration, the actual column must be added to the +_associated_ (`has_many`) model. In the case above, you would need to add a +column named `orders_count` to the `Customer` model. + +You can override the default column name by specifying a custom column name in +the `counter_cache` declaration instead of `true`. For example, to use +`count_of_orders` instead of `orders_count`: ```ruby class Order < ActiveRecord::Base belongs_to :customer, counter_cache: :count_of_orders end class Customer < ActiveRecord::Base - has_many :orders, counter_cache: :count_of_orders + has_many :orders end ``` -NOTE: You only need to specify the :counter_cache option on the "has_many side" of the association when using a custom name for the counter cache. +NOTE: You only need to specify the :counter_cache option on the `belongs_to` +side of the association. Counter cache columns are added to the containing model's list of read-only attributes through `attr_readonly`. |