Re: Removing auto-generated methods (set_sql)

[prev] [thread] [next] [Date index for 2004/06/14]

On Mon, Jun 14, 2004 at 01:30:03PM -0400, Perrin Harkins wrote:
> On Mon, 2004-06-14 at 12:57, William McKee wrote:
> > My script is being run in a mod_perl environment. I need to dynamically
> > generate a search based on input to a web form. This search requires a
> > join so I can't use standard CDBI methods. The WHERE clause could change
> > from call to call thus I regenerate it using SQL::Abstract.
> 
> Either give each search a unique name (by joining the searched fields or
> something)

Hi Perrin,

I had considered that possibility but then how can I call a dynamic
method? I don't think Perl would accept the following (at least in
strict mode):

    my $sql = qq~SELECT * FROM t1, t2~;
    my $sql_name = join("_", @fieldnames);
    MyDBI->set_sql($sql_name => $sql);
    MyDBI->$sql_name(@fieldvals);


> or do something like this:
> 
>     my $dbh = $self->db_Main();
>     my $sth = $dbh->prepare_cached(
>         some_sub_that_generates_your_sql()
>     );
> 
>     $sth->execute(@params);
>     my @results = $self->sth_to_objects($sth);

I think this might be the best solution; as Lance put it, when you only
use a hammer, everything looks like a nail.


> > See above. However, it seems like CDBI should allow a means to remove a
> > method if it is going to carp about redefining one.
> 
> It's not CDBI, it's Perl.  The set_sql method creates a sub based on the
> name you give it.  Perl will complain if you redefine a subroutine,
> which is what you are doing when you call set_sql twice with the same
> name.  You could turn that warning off, but you really should not be
> doing it this way.

I think I know what you are referring to but in this case I'm pretty
sure it's line 936 in CDBI:

	defined &{"$class\::$method"}
		and return $class->_carp("$method() already exists");


Thanks,
William

        -- 
        Knowmad Services Inc.
http://www.knowmad.com