[RDBO] cascading Manager queries
in Collection.pm, i have
sub count_assets {
my $self = shift;
return CollectionAsset::Manager-get_collection_assets_count(
require_objects = ['asset'],
query = [ collection_id = $self-
collection_id, @_ ],
);
}
sub count_assets_published {
my $self = shift;
return $self-count_assets('asset.pubstatus' = 'published',
@_);
}
and later:
my $count = $collection-count_assets_published(
[ \'t2.pubdate = NOW() - INTERVAL ? DAY' = $num_days ] #
t2 ~ asset
);
i can't refer to 'asset.pubdate' in this query param, because RDBOM
insists i use a scalar-ref here, and wisely avoids doing
substitutions when handed a scalar-ref, and mysql won't let me refer
to the table by its real name once it has been aliased.. since the
generated query aliases asset as t2, i have to use t2 here, though
not elsewhere. needless to day, it's a little confusing, especially
to future-maintenance-programmer.
any advice?
another thing i am struggling with a bit is allowing such helper
methods to modify both the query and manager_args. in the above
example, require_objects=['asset'] isn't required in the basic case
where it exists, but is there because methods like
count_assets_published need to refer to the assets.. seems common
enough, so maybe there is already a convenient way to merge manager
args in this case?
here is a bit of ugliness that hints at what i am after:
sub count_assets {
my $self = shift;
my ($manager_args, $query_args) =
_separate_manager_query_args(@_);
return Plex::RDBO::CollectionAsset::Manager-
get_collection_assets_count(
@$manager_args,
query = [ collection_id = $self-collection_id, @
$query_args ],
);
}
sub count_assets_published {
my $self = shift;
my ($manager_args, $query_args) =
_separate_manager_query_args(@_);
return $self-count_assets(
require_objects = ['asset'], @$manager_args,
query = [ 'asset.pubstatus' = 'published', @
$query_args ]
);
}
sub _separate_manager_query_args {
my @manager_args = @_;
my @query_args;
foreach my $i (0..$#manager_args) {
if ($manager_args[$i] eq 'query') {
@query_args = @{ (splice @manager_args, $i, 2)[1] };
last;
}
}
return ([EMAIL PROTECTED], [EMAIL PROTECTED]);
}
any advice? ;)
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Re: [RDBO] cascading Manager queries
On May 17, 2007, at 3:12 PM, Michael Reece wrote:
here is a bit of ugliness that hints at what i am after:
I think i do some similar stuff, so I'll give my advice -- which you
may be better off to not take ;)
I never use 'make manager methods'. i started it as a memory saver
because i use RDBO in 2 systems with 300+ sql tables/classes in each
- it was too too much overhead. instead i use dummy manager classes
and call get_objects directly.
that being said, since I only call get_objects directly , I found
that i could improve some memory use if i didn't use the default RDBO
manager class... instead I inherit off of my own class which wraps
the manager calls
if this makes any sense:
| - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - - - - - -
package MyApp::RDBO::Object::Item;
# setup here
1;
package MyApp::RDBO::Object::Item::Manager;
use MyApp::RDBO::Object::_ManagerCustom();
use base qw( MyApp::RDBO::Object::_ManagerCustom );
use MyApp::RDBO::Object::Item ();
sub object_class { 'MyApp::RDBO::Object::Item' }
# often no calls
1;
| - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - - - - - -
then in MyApp::RDBO::Object::_ManagerCustom I do some wonky things:
a) I have a bunch of standardized calls to get_objects, which just
subs in this to the query builder: object_class= $class-object_class
b) i rewrite get_objects , often in this form:
sub get_objects {
my ( $self , %kw_args )= @_;
# mess with kw_args ( often bless into class that provides indexing
etc )
my $results= Rose::DB::Object::Manager::get_objects ( $self , %
kw_args );
# mess with results ( often bless into class that provides indexing
etc )
return $results;
}
the point of this is as follows:
instead of using helper methods to modify the manger args, just
inherit from a different class and you can stuff anything you want
into the manager args,
then just hijack manager calls via your own subclass, which will call
the real rose manager and return results from it.
this method is slightly slower to run-- there are way more class
lookups , but it cuts down on enough memory that lets me run more
processes ( which gets me an overall better server load, as my
performance blocking is on the DB , not in perl )
-
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