I don't believe find_or_create can be safely used to increment a
counter, although I could be wrong.
From Resultset.pm:
my $exists = $self->find($hash, $attrs);
return defined $exists ? $exists : $self->create($hash);
A row could be inserted after the code checks for the row and before it
inserts the new row, which would result in an error.
Jason Kohles wrote:
On Feb 26, 2007, at 3:46 PM, Jim Spath wrote:
I am somewhat new to DBIx::Class and was wondering if the following
method is the best way to handle counter values. I've tested it, and
it works, but wasn't sure if there was a better way.
==================================================
(all model, table, and column names are made up)
(I'm using DBIx::Class under Catalyst, hence the $c)
==================================================
Seems like you could save yourself a lot of unnecessary logic...
$c->model( 'SomeDB::Counter' )->find_or_create({
counter_name => $counter_name
})->update({
counter => \'counter+1';
});
my $rows = $c->model('SomeDB::Counter')->search({
counter_name => $counter_name,
})->update({
counter => \'counter + 1',
});
if ($rows eq '0E0') {
eval {
$c->model('SomeDB::Counter')->create({
counter_name => $counter_name,
counter => 1,
});
};
if ($@) {
if ($@ =~ /duplicate entry/i) {
$rows = $c->model('SomeDB::Counter')->search({
counter_name => $counter_name,
})->update({
counter => \'counter + 1',
});
if ($rows eq '0E0') {
# couldn't update or insert counter
}
} else {
# unknown error on attempted insert
}
}
}
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