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author | Hongli Lai (Phusion) <hongli@phusion.nl> | 2008-09-16 12:42:26 +0200 |
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committer | Hongli Lai (Phusion) <hongli@phusion.nl> | 2008-09-16 12:50:50 +0200 |
commit | 86a0e98a79d9f03f431e55fc95f83783865d49e2 (patch) | |
tree | 698ab4a2924a311cb48dbf4ceb96e19f5d7341d3 | |
parent | 1fbae81e7f2ed64ae7c219e5669c7d68c2188d7a (diff) | |
download | rails-86a0e98a79d9f03f431e55fc95f83783865d49e2.tar.gz rails-86a0e98a79d9f03f431e55fc95f83783865d49e2.tar.bz2 rails-86a0e98a79d9f03f431e55fc95f83783865d49e2.zip |
Wrap overview documentation for ActiveRecord::Transactions::ClassMethods so that it's easier to read in a text editor with word wrapping enabled.
-rw-r--r-- | activerecord/lib/active_record/transactions.rb | 38 |
1 files changed, 23 insertions, 15 deletions
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb index f639ae3802..75b2460cf7 100644 --- a/activerecord/lib/active_record/transactions.rb +++ b/activerecord/lib/active_record/transactions.rb @@ -16,20 +16,25 @@ module ActiveRecord end end - # Transactions are protective blocks where SQL statements are only permanent if they can all succeed as one atomic action. - # The classic example is a transfer between two accounts where you can only have a deposit if the withdrawal succeeded and - # vice versa. Transactions enforce the integrity of the database and guard the data against program errors or database break-downs. - # So basically you should use transaction blocks whenever you have a number of statements that must be executed together or - # not at all. Example: + # Transactions are protective blocks where SQL statements are only permanent + # if they can all succeed as one atomic action. The classic example is a + # transfer between two accounts where you can only have a deposit if the + # withdrawal succeeded and vice versa. Transactions enforce the integrity of + # the database and guard the data against program errors or database + # break-downs. So basically you should use transaction blocks whenever you + # have a number of statements that must be executed together or not at all. + # Example: # # transaction do # david.withdrawal(100) # mary.deposit(100) # end # - # This example will only take money from David and give to Mary if neither +withdrawal+ nor +deposit+ raises an exception. - # Exceptions will force a ROLLBACK that returns the database to the state before the transaction was begun. Be aware, though, - # that the objects will _not_ have their instance data returned to their pre-transactional state. + # This example will only take money from David and give to Mary if neither + # +withdrawal+ nor +deposit+ raises an exception. Exceptions will force a + # ROLLBACK that returns the database to the state before the transaction was + # begun. Be aware, though, that the objects will _not_ have their instance + # data returned to their pre-transactional state. # # == Different Active Record classes in a single transaction # @@ -63,17 +68,20 @@ module ActiveRecord # # == Save and destroy are automatically wrapped in a transaction # - # Both Base#save and Base#destroy come wrapped in a transaction that ensures that whatever you do in validations or callbacks - # will happen under the protected cover of a transaction. So you can use validations to check for values that the transaction - # depends on or you can raise exceptions in the callbacks to rollback, including <tt>after_*</tt> callbacks. + # Both Base#save and Base#destroy come wrapped in a transaction that ensures + # that whatever you do in validations or callbacks will happen under the + # protected cover of a transaction. So you can use validations to check for + # values that the transaction depends on or you can raise exceptions in the + # callbacks to rollback, including <tt>after_*</tt> callbacks. # # == Exception handling and rolling back # - # Also have in mind that exceptions thrown within a transaction block will be propagated (after triggering the ROLLBACK), so you - # should be ready to catch those in your application code. + # Also have in mind that exceptions thrown within a transaction block will + # be propagated (after triggering the ROLLBACK), so you should be ready to + # catch those in your application code. # - # One exception is the ActiveRecord::Rollback exception, which will trigger a ROLLBACK when raised, - # but not be re-raised by the transaction block. + # One exception is the ActiveRecord::Rollback exception, which will trigger + # a ROLLBACK when raised, but not be re-raised by the transaction block. module ClassMethods # See ActiveRecord::Transactions::ClassMethods for detailed documentation. def transaction(&block) |