What is Perl DBI difference between with bind_columns and without it?

Question

What is the difference between the following code in perl dbi?

1.

while (my ($p1, $p2, $p3) = $sth->fetchrow_array()) {
    # ... some code ...
}

2.

$sth->bind_columns(\my ($p1, $p2, $p3));
while ($sth->fetch) {
    # ... some code ...
}

Both leads to the same result. Perlmonks advise on bind variant. I would appreciate if someone explain why.

Answer 1

the docs says, that binding is more efficient way to fetch data:

The binding is performed at a low level using Perl aliasing. Whenever a row is fetched from the database $var_to_bind appears to be automatically updated simply because it now refers to the same memory location as the corresponding column value. This makes using bound variables very efficient.