As discussed in the CB, databases tend to not tell the client how many rows they will return. The only way for the client to know how many rows will be returned is to count them as they're being read in.

The simplest solution would to read all the rows into memory before starting to process them. For example, replace 

while (my $row = $sth->fetch_arrayref()) {
   ...
}

[download]

with 

my $rows = $sth->fetchall_arrayref();
my $num_rows = @$rows;
foreach my $row (@$rows) {
   ...
}

[download]

If you need a DBI interface, then you can replace the code with 

my $rows = $sth->fetchall_arrayref();
my $num_rows = @$rows;

my $sponge = DBI->connect('dbi:Sponge:');
my $sponge_sth = $sponge->prepare(
   $sth->{Statement},
   {
      rows        => $rows,
      NAME        => $sth->{NAME},
      behave_like => $sth,
   }
);

while (my $row = $sponge_sth->fetch_arrayref()) {
   ...
}

[download]

It's too bad that DBD::Sponge doesn't override rows.

In reply to Re: Counting number of rows while working with Oracle by ikegami
in thread Counting number of rows while working with Oracle by denzil_cactus

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