[Dbix-class] DBIx and Arbitrary SQL through a custom ResultSource

[Peter Rabbitson]

Vangelis Katsikaros wrote:
> Hello
> 
> I had a problem following the instructions in "Arbitrary SQL through a 
> custom ResultSource" [1] since it gave me an error of `Can't locate 
> object method "result_source_instance"`
> 
> I found a solution in this perlmonk answer [2]. Indeed this works:
> 
> <code>---------------------------
> 
> package Dir::Dir::ComplexQuery;
> 
> use strict;
> use base 'DBIx::Class::Core';
> 
> __PACKAGE__->table( 'dummy_table_name' );
> __PACKAGE__->add_columns( qw/col1 col2 col3/ );
> __PACKAGE__->result_source_instance->name( \q!(complex SQL ... )! );
> 
> </code>---------------------------
> 
> and  I can normally do:
> ...->resultset('ComplexQuery')->search();
> 
> My questions are the following:
> 
>  1. The function "table" is the one from 
> DBIx::Class::ResultSourceProxy::Table as described in [3], right? I am 
> using `DBIx::Class::Schema::Loader` so I never had created a DBIx "class 
> table" myself.

Yes. What you witnessed is a side effect of a long standing wart.
This will be solved in the next release or two (bogus ->table calls
will no longer be needed). I could explain why this is currently
necessary, but I rather not since 1) this code is not for the faint
of heart and 2) it is entirely going away. I will however elaborate
more if you express further interest.

>  2. The "__PACKAGE__->table('table_name')" will NOT trigger a creation 
> of this table (in this case it's a view) to the actual DB, correct?
> Or is there a scenario where the creation of a view hac be triggered and 
> I can end up with a view named 'dummy_table_name' in my DB?

Creation is not something that ever happens automatically in DBIC.
Such a table definition *may* be included in a subsequent call to
deploy(), unless you follow the new improved way of doing things to
which Wolfgang already pointed you.

>  3. In which DBIx package is "result_source_instance" defined? I did 
> searched but I couldn't find it - maybe I am not searching the right way.
> 

See the answer to point 1, in particular this is one of the "not for
the faint of heart" references (the method is created at runtime, per
class, depending on certain conditions).

Cheers!