John,
Thank you for the quick reply.
I understand the complexity involved, and what we're looking for is the
quick storage & retrieval of the underlying data - I'll look at the
json/yaml serialization implementations.
Best,
Peter
John Siracusa wrote:
> On 12/4/06, Peter Leonard <[EMAIL PROTECTED]> wrote:
>> A second RDBO question - Does RDBO play nicely with Storable? Can I
>> freeze/thaw RDBO objects among various processes and get clean results?
>> (In a serial fashion, of course - I would not try to make updates to
>> the same object in several different places at once.)
>
> Freeze/thawing an unmodified RDBO-derived object will probably not do
> what you want because each object has a back-pointer to the metadata
> object for that class (which, in turn, has code references inside it).
> When you thaw it, you may have already loaded that class, and will
> therefore end up with two metadata objects for the same class, one of
> which is "dangling" (i.e., not connected to the metadata "registry"
> that knows how to look up the metadata object for each class).
>
> I've tried to implement Storable hooks for "db" (Rose::DB) objects,
> mostly just to discard the DBI $dbh (which won't survive freeze/thaw
> anyway), and that experience has shown me that Storable's hooks are
> pretty limited. (Or maybe I'm just doing it wrong...) If anyone
> wants to take a crack at making Storable hooks for RDBO that enable
> safe, coherent freeze/thaw, by all means, take a crack at it :)
>
> In the meantime, I suggest looking at the various
> serialization-related Helper methods like, column_values_as_json() and
> column_values_as_yaml(), and their reverse methods, init_with_json()
> and init_with_yaml()
>
> http://search.cpan.org/dist/Rose-DB-Object/lib/Rose/DB/Object/Helpers.pm
>
> Even if you don't use them, you can look at the implementation and
> then make your own, similar methods that use Storable for
> serialization instead. It should be quite simple.
>
> The basic idea is not to serialize the entire object, but instead just
> serialize the column values. Deserialization then becomes simple
> instantiation and init()ialization with the thawed column values (+/-
> the futzing with column/method name mapping--again, check the code for
> examples).
>
> (Serializing a "tree" of nested RDBO-derived objects could be done
> using a similar approach for each object in the tree, plus a bit of
> extra info detailing how to hook things back up later, but it'd be
> considerably more complex than doing single objects. It's on my
> long-term list...)
>
> -John
>
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