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Improve readonly examples and optimistic locking docs

* Relation#order can receive order attributes as different arguments,
  add example;
* Readonly does not handle deletion of records, only modification;
* locking_version column does not need to default to 0, Rails handles
  nil values;
* Change references from "set_locking_column" to "self.locking_column".
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1 parent 0d5f7da commit 31fce0192ee83ee13e2b17fdeefa712227019e49 @carlosantoniodasilva carlosantoniodasilva committed Jan 31, 2012
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10 activerecord/lib/active_record/locking/optimistic.rb
@@ -40,11 +40,13 @@ module Locking
# This locking mechanism will function inside a single Ruby process. To make it work across all
# web requests, the recommended approach is to add +lock_version+ as a hidden field to your form.
#
- # You must ensure that your database schema defaults the +lock_version+ column to 0.
- #
# This behavior can be turned off by setting <tt>ActiveRecord::Base.lock_optimistically = false</tt>.
- # To override the name of the +lock_version+ column, invoke the <tt>set_locking_column</tt> method.
- # This method uses the same syntax as <tt>set_table_name</tt>
+ # To override the name of the +lock_version+ column, set the <tt>locking_column</tt> class attribute:
+ #
+ # class Person < ActiveRecord::Base
+ # self.locking_column = :lock_person
+ # end
+ #
module Optimistic
extend ActiveSupport::Concern
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10 railties/guides/source/active_record_querying.textile
@@ -404,6 +404,8 @@ Or ordering by multiple fields:
<ruby>
Client.order("orders_count ASC, created_at DESC")
+# OR
+Client.order("orders_count ASC", "created_at DESC")
</ruby>
h3. Selecting Specific Fields
@@ -608,7 +610,7 @@ This method accepts *no* arguments.
h3. Readonly Objects
-Active Record provides +readonly+ method on a relation to explicitly disallow modification or deletion of any of the returned object. Any attempt to alter or destroy a readonly record will not succeed, raising an +ActiveRecord::ReadOnlyRecord+ exception.
+Active Record provides +readonly+ method on a relation to explicitly disallow modification of any of the returned objects. Any attempt to alter a readonly record will not succeed, raising an +ActiveRecord::ReadOnlyRecord+ exception.
<ruby>
client = Client.readonly.first
@@ -648,15 +650,13 @@ c2.save # Raises an ActiveRecord::StaleObjectError
You're then responsible for dealing with the conflict by rescuing the exception and either rolling back, merging, or otherwise apply the business logic needed to resolve the conflict.
-NOTE: You must ensure that your database schema defaults the +lock_version+ column to +0+.
-
This behavior can be turned off by setting <tt>ActiveRecord::Base.lock_optimistically = false</tt>.
-To override the name of the +lock_version+ column, +ActiveRecord::Base+ provides a class method called +set_locking_column+:
+To override the name of the +lock_version+ column, +ActiveRecord::Base+ provides a class attribute called +locking_column+:
<ruby>
class Client < ActiveRecord::Base
- set_locking_column :lock_client_column
+ self.locking_column = :lock_client_column
end
</ruby>

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