On Thu, Apr 30, 2009 at 07:21:45AM -0700, Morgon Hed wrote:
>
> Hi!
>
> I am currently evaluating DBIx::Class as a ORM-solution for a new system and
> I wonder either my design is flawed or DBIx::Class simply is not the right
> tool for me...
>
> I have a number of classes (all based on Moose) that I need to persist in an
> Oracle-database. The application is driven by messages that are received via
> Oracle Advanced Queuing.
>
> To process a message I have to retrieve a number of collaborating objects
> from the database (which then in memory form some sort of tree or graph)
> where calls are made from e.g. a child-object to a parent-object, and the
> other way around to finally reach an end-state at which point the whole
> object-graph should be persisted again to the database.
> So the whole thing should work like this:
>
> 1) dequeue message
> 2) build object-graph
> 3) process message in the graph
> 4) update graph in database
> 5) commit
>
> I.e. the final commit not only commits all changes to the object-graph but
> also the dequeuing of the message in one transaction.
>
> In such a context I would like each database-entity (given by it's primary
> key) to be represented by exactly one instance on the object-level (which
> Class::DBI actually does) but the philosophy of DBIx::Class seems to be
> different, for instance if I do this:
>
> my $h1 = $schema->resultset('Hubba')->find(1);
> my $h2 = $schema->resultset('Hubba')->find(1);
>
> I get two different instances both representing the same database-row which
> makes it a bit harder to build the graph I have in mind.
Yep, you do.
That's because the silly approach Class::DBI used caused memory leaks.
We don't like memory leaks.
> Can someone please give me some advice here?
Manage the scoping yourself - you'll find it's not actually that much code
and the finer grained control will make your life a lot easier.
I do heavy OODB style stuff in DBIC quite a bit - one of our clients was
kind enough to let me give: http://xrl.us/oubg6 at the PostgreSQL WEST
conference showing how we built it up for the http://airspace.co.uk/
hotel booking system - a small number of root classes and dozens of child
classes all FKed up nicely, and the scoping stuff didn't get in our way at
all.
--
Matt S Trout Catalyst and DBIx::Class consultancy with a clue
Technical Director and a commit bit: http://shadowcat.co.uk/catalyst/
Shadowcat Systems Limited
mst (@) shadowcat.co.uk http://shadowcat.co.uk/blog/matt-s-trout/
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