[Dbix-class] column accessor namespace

[Matt S Trout]

Dave Howorth wrote:
> In February I wrote:
>> I'm looking at moving from CDBI to DBIC for a variety of reasons.
>>
>> One of the problems I have with CDBI is that it puts the column accessor 
>> methods into the same namespace as its own class methods and 
>> plugin-sourced methods. This combined with Perl's inability to 
>> distinguish a class call from an instance call (except by adding code at 
>> the start of every method) means that there can be conflicts between 
>> column accessors and predefined methods. For example, my column 
>> accessors called 'sequence' and 'primary' both caused problems.
>>
>> So I was wondering what DBIC does about this issue. From a quick scan of 
>> the schemaintro doc, it looks like it has the same flaw. And a different 
>> set of predefined methods to conflict with :) For example, I really do 
>> have an accessor called 'belongs_to' :(
> 
> I got a few suggestions in reply to this and recently I started to 
> experiment with DBIC. It's been going really well. Thanks!
> 
> Today I tried to connect to the database that has a table with a column 
> called 'belongs_to'. It failed and because I'd forgotten about this 
> issue I initially found the error message very confusing:
> 
>    DBIx::Class::Schema::Loader::connection(): Can't fetch data as class
>    method at ./compare-db.pl line 76
> 
> My code is just:
> 
>    use QD1::Schema;
>    my $schema = QD1::Schema->connection($dsn, $dbuser, $dbpass);
> 
> and my Schema module is just:
> 
>    package QD1::Schema;
>    use base qw/DBIx::Class::Schema::Loader/;
>    __PACKAGE__->loader_options(relationships => 1);
>    1;
> 
> It would be nice if name clashes were detected and explicitly reported, 
> so as to produce meaningful error reports like CDBI does :)

You might like to have a play with Schema::Loader's dump_to_dir method, which 
would allow you to generate the DBIC definitions for stuff, and then tweak 
appropriately (changing __PACKAGE__->belongs_to into an explicit 
add_relationship call should get rid of that clash)

DBIC tends to overwrite methods rather than barfing like CDBI does since often 
you *can* overwrite a substantial number of provided methods without it 
failing. You could even, provided your "belongs_to" column doesn't need to be 
a belongs_to rel itself, simply add_columns it as the last thing in the file :)

-- 
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