Added automated optimistic locking if the field lock_version is present #384 [Michael Koziarski]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@295 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 18 insertions, 0 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index b97085cdba..8a0d75ee8a 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,23 @@
 *SVN*
 
+* Added automated optimistic locking if the field <tt>lock_version</tt> is present.  Each update to the
+  record increments the lock_version column and the locking facilities ensure that records instantiated twice
+  will let the last one saved raise a StaleObjectError if the first was also updated. Example:
+  
+    p1 = Person.find(1)
+    p2 = Person.find(1)
+    
+    p1.first_name = "Michael"
+    p1.save
+    
+    p2.first_name = "should fail"
+    p2.save # Raises a 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.
+
+  #384 [Michael Koziarski]
+
 * Added :counter_cache option to acts_as_tree that works just like the one you can define on belongs_to #371 [Josh]
 
 * Fixed quoting in validates_format_of that would allow some rules to pass regardless of input #390 [Dmitry V. Sabanin]