use strict;
use warnings;
use DBI;
use Carp qw( confess croak );

my $dbh = DBI->connect(
	"DBI:mysql:db=test1001;host=localhost",
	"pm", "correcthorsebatterystaple", {
		RaiseError => 1,
		AutoCommit => 0,
		PrintError => 0,	# do our own error handling.
	}
) or die "DB connect: $DBI::errstr";
 
eval {
	$dbh->do(q[ INSERT INTO ref(color) VALUES (?) ], undef, 'blue');
	my $last_ref = $dbh->last_insert_id('','','','');
	printf STDERR "last ref: %s\n", $last_ref;
	$dbh->do(q[ INSERT INTO t1(ref_id) VALUES (?) ], undef, $last_ref);
	my $last_t1 = $dbh->last_insert_id('','','','');
	printf STDERR "last t1: %s\n", $last_t1;
	$dbh->commit;
};
if ($@) {
	my $err = $@;	# save $@, as rolling back below could also fail.
	# attempt to rollback, which could also fail.
	eval { $dbh->rollback; } if ($dbh);
	confess( "DB error: $err" );
}

__END__

Schema used for the test1001 DB is as follows:

CREATE DATABASE test1001;
use test1001;
GRANT ALL ON test1001.* TO pm;
CREATE TABLE ref(
	id BIGINT PRIMARY KEY AUTO_INCREMENT,
	color TEXT
);
CREATE TABLE t1(
	id BIGINT PRIMARY KEY AUTO_INCREMENT,
	ref_id BIGINT REFERENCES ref(id)
		ON DELETE CASCADE
		ON UPDATE CASCADE
);