I have no idea about "standard" solution, but another idea for reference :)
Package Base; use base 'DBIx::Class::Core'; # parents' name should be a defined has_one or belong_to relationship has 'parents' => ( is => 'rw', isa => 'ArrayRef[Str]', builder => _build_parents, ); sub inflate_result { my $self = shift; my $ret = $self->next::method( @_ ); foreach my $relationship ( @{ $ret->parents } ) { my $parent = $ret->$relationship; my @columns = ... # @columns_in_$parent - @column_in_$ret foreach my $column ( @columns ) { # stolen from DBIx::Class's source no strict 'refs'; no warnings 'redefine'; my $method = join '::', ref $ret, $column; *$method = Sub::Name::subname( $method, sub { return $ret->$parent->$column; }); } } } ... package Target; extends 'Base'; ... package Host; extends 'Base'; __PACKAGE__->belong_to('target' => 'Target', 'target_id'); sub _build_parents {[qw/target/]} ... so just declare the attribute 'parents' in subclass is ok. the task is not typical for me, but interesting. On Fri, Jun 15, 2012 at 3:59 PM, Alex Erzin <eaa-h...@yandex.ru> wrote: > Yes, in some cases you are right, but you are saying about "long inheritance > chains" and other cases where inheritance is not enought flexible, > but i say about just one case in one place where inheritance is preferred for > me, and i try to find solution _how_ to implement inheritance, but not about > _why_not_ :) > > > 15.06.2012, 10:43, "Ben Tilly" <bti...@gmail.com>: >> The benefits of OOP are mostly in information hiding. >> >> If you're creating a bunch of long inheritance chains, you're probably >> doing OOP poorly. Composition is preferred. And maps *much* more >> naturally onto a relational database. >> >> On Thu, Jun 14, 2012 at 11:37 PM, Alex Erzin <eaa-h...@yandex.ru> wrote: >> >>> Hm... it really works, but where are benefits of OOP? ;) >>> There is no inheritance at all, and to access parent's properties I should >>> call parent directly, so inheritance just replaced with incapsulation, and >>> it's no one what i try to find. >>> >>> Some years ago we have implemented inheritance in ORM in some commercial >>> project in Perl, later I have swithed to java and have found Hibernate it >>> really cool with ORM. >>> But now I have returned to Perl and I think that DBIx::Class can help me >>> with ORM, but right now i'm confused that cannot find "standard" solution >>> for typical task. >>> >>> 15.06.2012, 10:25, "Hailin Hu" <i...@h2l.name>: >>>> Is it acceptable like something below >>>> >>>> package Target; >>>> ... >>>> package Host; >>>> ... >>>> __PACKAGE__->belong_to('target' => 'Target', 'target_id'); >>>> sub column_only_exists_in_target { >>>> my $self = shift; >>>> return $self->target->column_only_exists_in_target; >>>> } >>>> >>>> well, it is not a good solution, but it could work, I think :) >>>> >>>> On Fri, Jun 15, 2012 at 3:04 PM, Alex Erzin <eaa-h...@yandex.ru> wrote: >>>>> Hello, >>>>> >>>>> I need to implement table-per-class inheritance, as it simple made in >>>>> Hibernate in Java (more details can be found here >>>>> http://docs.jboss.org/hibernate/orm/4.1/manual/en-US/html/ch10.html#inheritance-tablepersubclass), >>>>> but cannot find right way how to do it in DBIx::Class. >>>>> >>>>> For example, I have two objects: Target (with properties ID, >>>>> Description) and Host (ID, Hostname, IP), Host inherited from Target, and >>>>> on table-level there are two tables Host and Target, joined by ID field. >>>>> >>>>> CREATE TABLE `mydb`.`target` ( >>>>> `target_id` INT NOT NULL , >>>>> `description` VARCHAR(45) NULL , >>>>> PRIMARY KEY (`target_id`) ) >>>>> >>>>> CREATE TABLE `mydb`.`host` ( >>>>> `target_id` INT NOT NULL , >>>>> `hostname` VARCHAR(45) NULL , >>>>> `ip` VARCHAR(45) NULL , >>>>> PRIMARY KEY (`target_id`) , >>>>> CONSTRAINT `fk_host_target` >>>>> FOREIGN KEY (`target_id` ) >>>>> REFERENCES `mydb`.`target` (`target_id` ) >>>>> ) >>>>> >>>>> How to implemeng there classes Target and Host, so it possible to write >>>>> >>>>> print $target->id(), $targer->description() >>>>> print $host->id(), $host->description(), $host->hostname(), $host->ip() >>>>> >>>>> ? >>>>> >>>>> I have no ideas how to implement inheritance, and all my experiments >>>>> are failed - from Host i cannot get access to parent properties like >>>>> description. >>>>> Could you help me please (with examples)? >>>>> >>>>> Thanks. >>>>> >>>>> -- >>>>> eaa@ >>>>> >>>>> _______________________________________________ >>>>> List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class >>>>> IRC: irc.perl.org#dbix-class >>>>> SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/ >>>>> Searchable Archive: >>>>> http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk >>>> _______________________________________________ >>>> List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class >>>> IRC: irc.perl.org#dbix-class >>>> SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/ >>>> Searchable Archive: >>>> http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk >>> -- >>> eaa@ >>> >>> _______________________________________________ >>> List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class >>> IRC: irc.perl.org#dbix-class >>> SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/ >>> Searchable Archive: >>> http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk >> >> _______________________________________________ >> List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class >> IRC: irc.perl.org#dbix-class >> SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/ >> Searchable Archive: >> http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk > > -- > eaa@ > > _______________________________________________ > List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class > IRC: irc.perl.org#dbix-class > SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/ > Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk _______________________________________________ List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class IRC: irc.perl.org#dbix-class SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/ Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk