Sorry it took me awhile to get to this. It’s longish but thread is dead so I’m skipping <readmore/>. Transactions are great and trivial to use and even nest with DBIx::Class; DBIx::Class::Storage::TxnScopeGuard. You can generate a schema from an existing DB—DBIx::Class::Schema::Loader—so you don’t have to write the BEGIN style code; it’s only there for an encapsulated example.

#!/usr/bin/env perl
use strictures;
use 5.010;
BEGIN { # Sample packages.
    package MyApp::Schema::Address {
        use parent "DBIx::Class::Core";

        __PACKAGE__->table("address");
        __PACKAGE__->add_columns( id => { data_type => 'integer',
                                          is_auto_increment => 1 },
                                  address => { data_type => 'varchar',
                                               size      => '100' } );
        __PACKAGE__->set_primary_key("id");
    };

    package MyApp::Schema {
        use parent "DBIx::Class::Schema";
        # For real -> __PACKAGE__->use_namespaces;
        __PACKAGE__->load_classes("Address"); # <- For this example.
    };
}

my $use_transaction = shift;
say "Doing it ", $use_transaction ? "with" : "without", " transaction.
+";

my $schema = MyApp::Schema->connect("dbi:SQLite::memory:");
$schema->deploy;

# Create some addresses.
my $addresses = $schema->resultset("Address");
for ( 1 .. 10 )
{
    $addresses->create({ address => "$_ Street" });
}

my $count = $addresses->count;
eval {
    $use_transaction ?
        process_with_txn_guard()
        :
        process_without_txn_guard();
};

if ( $@ ) {
    print "We had an error! $@";
    say "We have ", $addresses->count, " left in the DB";
    say "Sucks to be you..." unless $count == $addresses->count;
}

exit 0;

sub process_without_txn_guard {
    for my $address ( $addresses->all )
    {
        # Do some local processing with $address.
        say "Deleting ", $address->address;
        $address->delete;
        die "Bad stars" if rand(1) > .8; # Intermittent failure.
    }
    # Do remote "global" processing with all addresses.
}

sub process_with_txn_guard {
    my $guard = $schema->txn_scope_guard;
    process_without_txn_guard();
    $guard->commit;
}

__END__
moo@cow~>pm-1142097
Doing it without transaction.
Deleting 1 Street
Deleting 2 Street
Deleting 3 Street
We had an error! Bad stars at pm-1142097 line 57.
We have 8 left in the DB
Sucks to be you...

moo@cow~>pm-1142097 with_txn
Doing it with transaction.
Deleting 1 Street
Deleting 2 Street
Deleting 3 Street
We had an error! Bad stars at pm-1142097 line 58.
We have 10 left in the DB

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In reply to Re: DBI and sqlite concurrency by Your Mother
in thread DBI and sqlite concurrency by MorayJ

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