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@
>>>
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>>
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>
> --
> eaa@
>
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