|
|
Posted by Steve on 12/19/07 16:55
"Gordon" <gordon.mcvey@ntlworld.com> wrote in message
news:94987e96-200d-4909-ab1a-f75049c41da6@t1g2000pra.googlegroups.com...
> On Dec 19, 12:33 pm, Tim Hunt <tim.n.h...@gmail.com> wrote:
>> On Dec 18, 5:31 pm, Gordon <gordon.mc...@ntlworld.com> wrote:
>>
>>
>>
>> > I am currently working on some code for my CMS that creates a site
>> > folder, then creates all the necessary child folders inside it. The
>> > method that creates folders needs to insert into 2 tables so it wraps
>> > the operation in a transaction. (psuedocode below)
>>
>> > public function createItem ($parent)
>> > {
>> > $this -> database -> beginTransaction ();
>> > $this -> database -> query ('INSERT INTO items (param1,
>> > param2 ... ) values (val1, val2 ... )');
>> > $newId = myMethodForGettingInsertId ();
>> > $this -> database -> query ('INSERT INTO folders (id, param3 ... )
>> > values ($newId, val3 ... )');
>> > $this -> database -> commit ();
>> > return ($newId);
>>
>> > }
>>
>> > (the real code is obviously a lot more sophisticated and has all the
>> > error checking and rollbacks and what have you but the mock up code
>> > below is clearer regarding the intent of the method)
>>
>> > In my site creating class I have something along the lines of
>>
>> > public function createItem ($parent)
>> > {
>> > $this -> database -> beginTransaction ();
>> > $newId = parent::createItem ($parent);
>> > parent::createItem ($newId, 'images');
>> > parent::createItem ($newId, 'css');
>> > parent::createItem ($newId, 'other_stuff');
>> > $this -> database -> commit ();
>>
>> > }
>>
>> > This obviously causes an exception. I can take the transaction code
>> > out of my folder class but the creation of a folder should be atomic.
>> > I could leave it out of the site creation class, but I really do need
>> > site creation to be atomic as well.
>>
>> > Is there a way of determining that I am inside a transaction before
>> > attempting to start one?
>>
>> Only if you keep track of it yourself, write your own
>> beginTransaction() and commit() methods and use a transaction count
>> variable.
>>
>> All calls to your own beginTransaction() and commit() methods
>> increment/decrement the transaction counter respectively. Only the
>> first call to beginTransaction calls $this->database->beginTransaction
>> and $this->database->commit() is only called when the transaction
>> counter reaches 0 again.
>
> Yes, that sounds like a cunning plan. I can add that into my PDO
> wrapper easily enough I think. Thanks for the help.
being careful to note that you can rollback an entire set of transactional
statments on a per-connection basis as well as rolling back individual
statements.
Navigation:
[Reply to this message]
|