[Dbix-class] DBIx::Class::Relationship::HasOne

[Hartmaier Alexander]

Hi list!

I've just added this plugin to my local svn snapshot to make writing native dbic schema classes easier.

e.g instead of writing

__PACKAGE__->add_relationship(
    cd => 'App::CD',
    { 'foreign.id_cd' => 'self.cd' },
);

only

__PACKAGE__->has_one('cd', 'App::CD');

is needed ;-)

Multiple key relationships are supported to with the following syntax:

__PACKAGE__->has_one('accessorname', 'Foreign::Class', {foreign_key1 => self_key1, foreign_key2 => self_key2});

As with all new things this needs extensive testing which I'll do next week but feel free to test it too ;-)

To enable 'has_one' here is the svn diff against the current snapshot:

*snip*
svn diff
Index: lib/DBIx/Class/CDBICompat/HasA.pm
===================================================================
--- lib/DBIx/Class/CDBICompat/HasA.pm   (Revision 184)
+++ lib/DBIx/Class/CDBICompat/HasA.pm   (Arbeitskopie)
@@ -22,9 +22,10 @@
   my ($pri, $too_many) = keys %{ $f_class->_primaries };
   $self->throw( "has_a only works with a single primary key; ${f_class} has more" )
     if $too_many;
-  $self->add_relationship($col, $f_class,
-                            { "foreign.${pri}" => "self.${col}" },
-                            { accessor => 'filter' } );
+  #$self->add_relationship($col, $f_class,
+  #                          { "foreign.${pri}" => "self.${col}" },
+  #                          { accessor => 'filter' } );
+  $self->has_one($col, $f_class);
   return 1;
 }
 
Index: lib/DBIx/Class/Relationship.pm
===================================================================
--- lib/DBIx/Class/Relationship.pm      (Revision 184)
+++ lib/DBIx/Class/Relationship.pm      (Arbeitskopie)
@@ -5,7 +5,7 @@
 
 use base qw/DBIx::Class Class::Data::Inheritable/;
 
-__PACKAGE__->load_own_components(qw/Accessor CascadeActions ProxyMethods Base/);
+__PACKAGE__->load_own_components(qw/Accessor CascadeActions ProxyMethods Base HasOne/);
 
 __PACKAGE__->mk_classdata('_relationships', { } );
*snip*


It already gets used by the CDBI compat layer for the has_a relation and passes all tests ;-)

And the new package:

*snip*
package DBIx::Class::Relationship::HasOne;

use strict;
use warnings;

sub has_one {
  my ($class, $acc_name, $f_class, $conds, $args) = @_;
  eval "require $f_class";
  # single key relationship
  if (not defined $conds && not defined $args) {
    my ($pri, $too_many) = keys %{ $f_class->_primaries };
    my $acc_type = ($class->_columns->{$acc_name}) ? 'filter' : 'single';
    $class->add_relationship($acc_name, $f_class,
      { "foreign.${pri}" => "self.${acc_name}" },
      { accessor => $acc_type }
    );
  }
  # multiple key relationship
  else {
    my %f_primaries = %{ $f_class->_primaries };
    my $conds_rel;
    for (keys %$conds) {
      $conds_rel->{"foreign.$_"} = "self.".$conds->{$_};
      # primary key usage checks
      if (exists $f_primaries{$_}) {
        delete $f_primaries{$_};
      }
      else
      {
        $class->throw("non primary key used in join condition: $_");
      }
    }
    $class->throw("not all primary keys used in multi key relationship!") if keys %f_primaries;
    $class->add_relationship($acc_name, $f_class,
      $conds_rel,
      { accessor => 'single' }
    );
  }
  return 1;
}

1;
*snip*

Looking forward for feedback!

With kind regards
Alexander Hartmaier

T-Systems Austria GesmbH
Rennweg 97-99 1030 Wien

phone: +43 57057-4320
fax: +43 57057-95-4320
mobile: +43 676 8642 4320
mail: alexander.hartmaier at t-systems.at
internet: http://www.t-systems.at



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