Skye Shaw wrote:
2011/2/8 Peter Rabbitson <[email protected]>:
Skye Shaw wrote:
Is it possible to have DBIC populate a newly created instance with the
underlying table's defaults when a value isn't provided?
The reason is that having every insert be followed by a select is...
how shall I put it, insane?!
Insane implementations shouldn't disqualify very sane ideas.
I simply answered your question:
...Is it possible to have DBIC populate a newly created instance with
the *underlying table's defaults*...
which I apparently misunderstood.
An ORM should know the details of the tables and columns its mapping.
Particularly in cases where the user actually specifies this
information within the ORM's method calls:
__PACKAGE__->add_columns(
active => {
data_type => 'tinyint',
default_value => 1
}
)
Oh I see. You are assuming default_value is a well-defined attribute
that always contains something that makes sense in perl-land. However
it is simply an advisory value used exclusively by deploy(), and hence
can contain weird stuff like \'current_timestamp()', or something even
more esoteric. Even the plain scalar values can not be trusted, as
already existing schemas can very well contain garbage (courtesy of
botches DBIx::Class::Schema::Loader runs), since this field has never
been expected to be authoritative. Hence overloading the existing
attribute with new meaning would be unwise.
What you want is the (admittedly misnamed)
http://search.cpan.org/~abraxxa/DBIx-Class-0.08127/lib/DBIx/Class/Row.pm#discard_changes_%28$attrs?%29
Well, what I want is $db->resultset('Account')->create/new to respect
the underlying table's defaults.
This is something you can do today with DBIx::Class::DynamicDefault,
with the odd quirk that your values will need to be returned by a
coderef (due to the implementation and scope of this module).
If an account table has an attribute named active that defaults to 1,
I would expect that, when using an ORM, newly instantiated
-nevertheless persisted- instances of the Account class would default
to 1 too. Not the opposite. IMHO the current behavior is broken.
Bottom line - 'default_value' has a confusing name, sorry about that :)
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