diff options
Diffstat (limited to 'activerecord/lib/active_record/locking')
-rw-r--r-- | activerecord/lib/active_record/locking/optimistic.rb | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb index ff9899d032..7fa7e267d8 100644 --- a/activerecord/lib/active_record/locking/optimistic.rb +++ b/activerecord/lib/active_record/locking/optimistic.rb @@ -23,6 +23,16 @@ module ActiveRecord # p2.first_name = "should fail" # p2.save # Raises a ActiveRecord::StaleObjectError # + # Optimistic locking will also check for stale data when objects are destroyed. Example: + # + # p1 = Person.find(1) + # p2 = Person.find(1) + # + # p1.first_name = "Michael" + # p1.save + # + # p2.destroy # 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. # @@ -39,6 +49,7 @@ module ActiveRecord base.lock_optimistically = true base.alias_method_chain :update, :lock + base.alias_method_chain :destroy, :lock base.alias_method_chain :attributes_from_column_definition, :lock class << base @@ -98,6 +109,28 @@ module ActiveRecord end end + def destroy_with_lock #:nodoc: + return destroy_without_lock unless locking_enabled? + + unless new_record? + lock_col = self.class.locking_column + previous_value = send(lock_col).to_i + + affected_rows = connection.delete( + "DELETE FROM #{self.class.quoted_table_name} " + + "WHERE #{connection.quote_column_name(self.class.primary_key)} = #{quoted_id} " + + "AND #{self.class.quoted_locking_column} = #{quote_value(previous_value)}", + "#{self.class.name} Destroy" + ) + + unless affected_rows == 1 + raise ActiveRecord::StaleObjectError, "Attempted to delete a stale object" + end + end + + freeze + end + module ClassMethods DEFAULT_LOCKING_COLUMN = 'lock_version' |