[html-formfu] Automatic constraints from DBIC data types

[Carl Franks]

On 10/10/2007, Zbigniew Lukasiak <zzbbyy at gmail.com> wrote:
> Hi there,
>
> I can start work on the DBIC constraints - but I am still hesitating
> about the api.  I've started with a subroutine that works similarly to
> the other HTML::FormFu::DBIC subs:
>
> constraints_from_dbic( $dbic, $form );
>
> It would just scan all form fields and add the constraints from the
> $dbic row.  The problem I see is with configuration - since normal
> constraints are added from the yaml config like:
>
> elements:
>       - type: Text
>         name: foo
>         constraints:
>           - type: Length
>             min: 8
>
> So this would be a bit different.  We could also have something like:
> elements:
>       - type: Text
>         name: foo
>         constraints:
>           - type: Length
>             min: 8
>           - type: From_DBIC
>             dbic_field: foofoo
>
> But then when converting from a vanilla FormFu to FormFu::DBIC you
> would have to edit the whole yaml config.
>
> Hmm.  Which one do  you prefer? Any other api ideas?

I've just been thinking about this, and going through the archives, to
see what previous discussion there had been - and discovered that
$form already has a constraints_from_dbic() method!

I'd completely forgotten that I'd done it, and haven't even used it yet.

It creates constraints based on column_info(), for length of field,
signed and unsigned integers, and Set constraints based on an enum/set
column's list of values.
It also has basic support for relationships via:
    $form->constraints_from_dbic(
        $result_set,
        { column => $related_result_set }
    );

See:
lib/HTML/FormFu/ObjectUtil.pm constraints_from_dbic()
t/form/constraints_from_dbic.t
t/form/constraints_from_dbic_rs.t
t/lib/Schema/Schema.pm
t/lib/Schema/Schema/Person.pm
t/lib/Schema/Schema/Dongle.pm

Has anyone used this functionality?
It's not documented, so it's probably safe to make changes if necessary.

Carl