[Dbix-class] RFC - has_subset

[Matt S Trout]

On Mon, Mar 31, 2008 at 12:45:04PM +0100, Daniel Ruoso wrote:
> Hi,
> 
> I'm working on an application that have the following classes:
> 
>   TaskType --- has_many ---> TaskTypeFile
> 
> but, that can actually be seen as two relationship types:
> 
>           ____ has_many { type => input } __
>          /                                  \
>   TaskType                            TaskTypeFile
>          \____ has_many { type => output }__/
> 
> Or, this could be seen as:
> 
>                                 TaskTypeFile
>                                /\          /\
>                                 |          |
>                                is          is
>                                 |          |
>                            InputFile     OutputFile
>            _______ has_many__/            |
>           /                               |
>   TaskType --------------- has_many ------/
> 
> But one could see InputFile and OutputFile simply as a subset of
> TaskTypeFile, and once this is done, we can keep the simplicity of
> the first diagram, and filter on the TaskTypeFile as needed, which also
> enables the input/output view independent on the TaskType relationship.
> 
> So, instead of doing
> 
> $tasktypers->input_files
> $tasktypers->output_files
> 
> I could do
> 
> $tasktypers->files->input
> $tasktypers->files->output

So you have one has_many, 'files', and a custom resultset class providing
'input' and 'output' methods.

I don't see how this is a relationship/component?

-- 
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