Re: anyway to determine # rows before fetch loop ends and without seperate count(*)
- From: denials@xxxxxxxxx (Dan Scott)
- Date: Wed, 16 Nov 2005 17:46:30 -0500
On 11/16/05, Rob Craig <rcraig@xxxxxxxxxxxxxxxxxxxx> wrote:
> I am using DBD::mysql and I can get the number of rows by assigning the
> result of the execute to a scalar:
>
> my $rows = $sth->execute or die "Couldn't execute statement: " .
> DBI->errstr;
>
> maybe this doesn't work with DBD::Oracle?
>
> Rob
When you execute a SELECT statement in MySQL, it (by default)
immediately returns all of the rows back to you under the covers,
which is why it is able to give you a row count. Woe betide you if
your SELECT statement returns a million rows.
>
> listmail@xxxxxxxxxxxx wrote:
> #Here's an example which shows what I am trying to accomplish. If I
> can determine the number of rows before pushing the data, this can
> simply things for #me when processing the data throught my scripts.
> #
> use warnings;
> use strict;
> use DBI;
> use DBD::Oracle;
>
> my $sql=q{ select name, location
> from mytable
> };
>
> my $dbh;
>
> eval {
> $dbh = DBI->connect("dbi:Oracle:MYDB",
> 'dbuser', 'dbpass',
> {
> RaiseError => 1,
> AutoCommit => 0,
> ora_session_mode => 0
> }
> );
> };
>
> if ( $@ ) {
> outprint('end',"$DBI::errstr\n");
> }
>
> my $sth=$dbh->prepare($sql) or die "Couldn't prepare statement: " . DBI-
>
>
> errstr;
>
> $sth->execute or die "Couldn't execute statement: " . DBI->errstr;
>
> my $ary;
>
> while ($ary = $sth->fetchrow_array()) {
> #I need to determine number of rows as this will affect
> whether a matrix is used or not
> #a boolean variable $matrix could be returned or a ref
> check done so that the data
> #processing code can act accordingly
> #$sth->rows only shows total rows after the while loop
> is processed
> #Can I accomplish this without a seperate count(*)
> statement?
> #
> #push @newary,[ @{$ary} ]; # if more than one row
> #or
> #push @newary, @{$ary} ; # single row
> }
>
> $sth->finish;
>
> $dbh->disconnect;
> #
> #ActivePerl 5.8.7 813
> #ppm
> #-DBD-Oracle 1.16
> #-DBI 1.48
>
>
>
>
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>
>
>
.
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