use Win32::ODBC;
use Data::Dumper;

use strict;

my $Data = new Win32::ODBC("myDSN") || die "failed\n";
$Data->Run("DROP TABLE test1");
$Data->Run('CREATE TABLE test1(a number, b char(1))');
for (1..50) {
        my $statement = "INSERT INTO test1 VALUES($_, ' ')";
        $Data->Run($statement);
}
$Data->Sql("SELECT * FROM test1");

while (1) {
    my @Rows = FetchRows($Data, 4);#fetch 4 rows each time 
    print Dumper(\@Rows);
    last if $Rows[0];#$Rows[0] is used to indicate whether we reached the end of active dataset
}

sub FetchRows {
    my ($Connection, $Rows) = @_;
    my @Rows;
    push @Rows, 0; #
    for (1..$Rows) {
        if ($Data->FetchRow()) {
            my %hash = $Data->DataHash();
            push @Rows, \%hash;
        } else {
            $Rows[0] = 1;
        }
    }
    return @Rows;
}