[EP-tech] Re: Understanding how data objects link

[Ian Stuart]

On 15/01/14 09:39, Ian Stuart wrote:
> When I use the code, I start with a user_id, and want to get the list of
> postcards associated with that user, so I have code thus:
>
>     # Before we do anything - we need to get the subscriber object
>     my $subs_ds = $session->get_repository->get_dataset("subscriber");
>     my $subscriber;
>
>     { # Localise this search
>       my $searchexp = EPrints::Search->new(
>         session     => $session,
>         dataset     => $subs_ds,
>       );
>       $searchexp->add_field( $subs_ds->get_field("userid"), $user_id );
>       warn $searchexp->render_description->toString;
>       my $results = $searchexp->perform_search;
>
>       if ($results->count) {
>         my @records = $searchexp->perform_search->slice(0,1); # Get
> records from position 0, for a count of 1 records
>         $subscriber = $records[0]
>       } else {
>         $subscriber = EPrints::DataObj::Subscriber->create( $session,
> {userid => $user_id }, $subs_ds );
>       }
>     }
>
>     # Having got a subscriber object, lets get a list of postcards they have
>     # Postcards are 1 email address and some number of repositories
>     warn "got subscriber " . $subscriber->get_id . "\n";
>     my $postcards = $subscriber->get_value( 'postcards' );
>
> This code successfully returns a matching "Subscriber", however the
> final line in that code is causing me problems... I get the error
>
>     dataset postcard has no field: datasetid
>
> I have double-checked my code against that of EPrints::DataObj::EPrint
> and EPrints::DataObj::Document - neither of them have a datasetid field,
> and my own objects are creating records in exactly the same way!

if I add the following code above the sample given, I successfully get 
the response that eprint ID 86126 has 1 document:

   my $eps_ds = $session->get_repository->get_dataset("eprint");
   my $ep;

   { # Localise this search
     my $searchexp = EPrints::Search->new(
       session     => $session,
       dataset     => $eps_ds,
     );
     $searchexp->add_field( $eps_ds->get_field("eprintid"), 68126 );
     warn $searchexp->render_description->toString;
     my $results = $searchexp->perform_search;

     if ($results->count) {
       my @records = $searchexp->perform_search->slice(0,1); # Get 
records from position 0, for a count of 1 records
       $ep = $records[0]
     }
   }

   # Having got a subscriber object, lets get a list of postcards they have
   # Postcards are 1 email address and some number of repositories
   warn "got eprint " . $ep->get_id . "\n";
   my $documents = $ep->get_value( 'documents' );
   warn "Got " . scalar @{$documents} . " documents\n";

This seems to confirm I've got something wrong in my packages.... but 
/what/ and /where/ is the question...

-- 

Ian Stuart.
Developer: ORI, RJ-Broker, and OpenDepot.org
Bibliographics and Multimedia Service Delivery team,
EDINA,
The University of Edinburgh.

http://edina.ac.uk/

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