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Re^2: dbi_query_iterator and my misunderstanding the $row

by jfroebe (Parson)
on Mar 01, 2007 at 22:04 UTC ( [id://602791]=note: print w/replies, xml ) Need Help??

in reply to Re: dbi_query_iterator and my misunderstanding the $row
in thread dbi_query_iterator and my misunderstanding the $row

Thanks! But why return $oldrow->[0] instead of just $row->[0]?

my $oldrow = $row; $row = $sth->fetchrow_arrayref; return $oldrow->[0];

Jason L. Froebe

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Re^3: dbi_query_iterator and my misunderstanding the $row
by japhy (Canon) on Mar 02, 2007 at 13:43 UTC
    Oh, sorry. Maybe I misunderstood. Does the code actually work, and you want to know why it works?

    $oldrow is the previous row. The function that builds the iterator stores the first row before it creates the iterator function:

    sub dbi_query_iterator { my ($sth, @params) = @_; $sth->execute(@params) or return; # get the first row of results NOW my $row = $sth->fetchrow_arrayref(); return Iterator { my $action = shift() || 'nextval'; if ($action eq 'exhausted?') { return ! defined $row; } elsif ($action eq 'nextval') { # save the current row of results my $oldrow = $row; # get the next row of results $row = $sth->fetchrow_arrayref; # return the previous row (before we advanced) return $oldrow->[0]; } } }

    Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
    How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart

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