Veltro has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,

The following is from the documentation at DBIx::Class::ResultSet which describes a populate method that can take an entire hash structure to populate related tables:

$schema->resultset("Artist")->populate([
   { artistid => 4, name => 'Manufactured Crap', cds => [
      { title => 'My First CD', year => 2006 },
      { title => 'Yet More Tweeny-Pop crap', year => 2007 },
    ],
   },
   { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
      { title => 'My parents sold me to a record company', year => 200
+5 },
      { title => 'Why Am I So Ugly?', year => 2006 },
      { title => 'I Got Surgery and am now Popular', year => 2007 }
    ],
   },
]);

[download]

I am basically looking for the inverse action of populate that instantly gives me a Perl hash with exactly 'that' format with the results from the database. In the following code I'll try to illustrate this with the method to_data that is a fictional method to demonstrate what I would like to achieve:

my $artistsAndTitles = $schema->resultset('Artist')->
   search(...)->search_related_rs('cds', {...})->as_data

# or another case using a accessor-method with the name 'cds' from a m
+any_to_many relation:

my $artistsAndTitles = $schema->resultset('Artist')->
   cds()->as_data ;

[download]

The expected result that I hope for in $artistsAndTitles is a Perl array/hash construct like:

[
   { artistid => 4, name => 'Manufactured Crap', cds => [
      { title => 'My First CD', year => 2006 },
      { title => 'Yet More Tweeny-Pop crap', year => 2007 },
    ],
   },
   { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
      { title => 'My parents sold me to a record company', year => 200
+5 },
      { title => 'Why Am I So Ugly?', year => 2006 },
      { title => 'I Got Surgery and am now Popular', year => 2007 }
    ],
   }
]

[download]

I done quite a bit of reading regards DBIx::Class but can't find a method to do this. Is there any method 'out-of-the-box' that can do this (correctly, taken different types of relations in account such as one-to-many or many-to-many)?

With best regards,

Veltro

Replies are listed 'Best First'.
Re: DBIx::Class::ResultSet disired hash output including related items
by spadacciniweb (Curate) on Feb 26, 2019 at 13:51 UTC
    If I have undestand, you have to use ResultClass::HashRefInflator
    An example in documentation page.

    ($_="nzz ojjdloobnf jjt tqqbebd77jojxfc")=~y~wb-zg2-5c96-8~aa-z0-9~s=~s~~~s;$_=~y~5-8~fuck~;print
[reply]

      I have tried something like the following,

      my $artists = $schema->resultset('Artist') ;
# $artists->result_class
   ('DBIx::Class::ResultClass::HashRefInflator'); # will cause errors
my $artistAndTitles = $artists->next->cds() ;
$artistAndTitles->result_class
   ('DBIx::Class::ResultClass::HashRefInflator');
while (my $hashref = $artistAndTitles->next) {
  print Dumper($hashref) ;
}

      [download]

      But this way I only get a 'shallow' hash from the 'cds' result subset for only one row at a time instead of each Artist + all the titles.

      Maybe there is another way? Examples appreciated.

[reply]
[d/l]
        Documentation report:

        ... Specifying this class as a result_class for a resultset will change $rs->next to return a plain data hash-ref (or a list of such hash-refs if $rs->all is used

        so last lines of your code turn in 
        my @hashref = $artistAndTitles->all;
print Dumper(\@hashref) ;

        [download]

        ($_="nzz ojjdloobnf jjt tqqbebd77jojxfc")=~y~wb-zg2-5c96-8~aa-z0-9~s=~s~~~s;$_=~y~5-8~fuck~;print
[reply]
[d/l]

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