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author | Jeremy Kemper <jeremy@bitsweat.net> | 2007-05-25 21:31:44 +0000 |
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committer | Jeremy Kemper <jeremy@bitsweat.net> | 2007-05-25 21:31:44 +0000 |
commit | c4a31560bd686cbd16b4af20e764a9a0660cd170 (patch) | |
tree | 348ad796c4b80d0a227640bf135141c417f4dfbf /activerecord/lib | |
parent | 38deb0ed83c54444e091d39382dcfe58e1c0bd05 (diff) | |
download | rails-c4a31560bd686cbd16b4af20e764a9a0660cd170.tar.gz rails-c4a31560bd686cbd16b4af20e764a9a0660cd170.tar.bz2 rails-c4a31560bd686cbd16b4af20e764a9a0660cd170.zip |
Optimistic locking: revert the lock version when an update fails. Closes #7840. Also return the number of affected rows instead of true.
git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6843 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
Diffstat (limited to 'activerecord/lib')
-rw-r--r-- | activerecord/lib/active_record/locking/optimistic.rb | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb index 23e7239d5e..d8f9dee372 100644 --- a/activerecord/lib/active_record/locking/optimistic.rb +++ b/activerecord/lib/active_record/locking/optimistic.rb @@ -2,7 +2,7 @@ module ActiveRecord module Locking # == What is Optimistic Locking # - # Optimistic locking allows multiple users to access the same record for edits, and assumes a minimum of + # Optimistic locking allows multiple users to access the same record for edits, and assumes a minimum of # conflicts with the data. It does this by checking whether another process has made changes to a record since # it was opened, an ActiveRecord::StaleObjectError is thrown if that has occurred and the update is ignored. # @@ -16,10 +16,10 @@ module ActiveRecord # # 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 # @@ -53,16 +53,16 @@ module ActiveRecord private def attributes_from_column_definition_with_lock result = attributes_from_column_definition_without_lock - + # If the locking column has no default value set, # start the lock version at zero. Note we can't use # locking_enabled? at this point as @attributes may # not have been initialized yet - + if lock_optimistically && result.include?(self.class.locking_column) result[self.class.locking_column] ||= 0 end - + return result end @@ -73,18 +73,25 @@ module ActiveRecord previous_value = send(lock_col) send(lock_col + '=', previous_value + 1) - affected_rows = connection.update(<<-end_sql, "#{self.class.name} Update with optimistic locking") - UPDATE #{self.class.table_name} - SET #{quoted_comma_pair_list(connection, attributes_with_quotes(false))} - WHERE #{self.class.primary_key} = #{quote_value(id)} - AND #{self.class.quoted_locking_column} = #{quote_value(previous_value)} - end_sql + begin + affected_rows = connection.update(<<-end_sql, "#{self.class.name} Update with optimistic locking") + UPDATE #{self.class.table_name} + SET #{quoted_comma_pair_list(connection, attributes_with_quotes(false))} + WHERE #{self.class.primary_key} = #{quote_value(id)} + AND #{self.class.quoted_locking_column} = #{quote_value(previous_value)} + end_sql - unless affected_rows == 1 - raise ActiveRecord::StaleObjectError, "Attempted to update a stale object" - end + unless affected_rows == 1 + raise ActiveRecord::StaleObjectError, "Attempted to update a stale object" + end - return true + affected_rows + + # If something went wrong, revert the version. + rescue Exception + send(lock_col + '=', previous_value) + raise + end end module ClassMethods |