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Re^6: MongoDB replacing an array

by neilwatson (Curate)
on Aug 26, 2012 at 21:56 UTC ( #989882=note: print w/ replies, xml ) Need Help??


in reply to Re^5: MongoDB replacing an array
in thread MongoDB replacing an array

There is not much more to show. Most is boring data manipulation that leads to the final array. The array holds only numbers. Nothing embedded.

my $conn = MongoDB::Connection->new; my $db = $conn->mydb || die "$!"; my ($col, $cols, @cols, $q, $doc, @b, @c, @new, $x, $date, $l, $host); + @cols = $db->collection_names; foreach $cols (@cols) {

Above a loop through some collections and for each make the new array. Then I try to replace the array.

if ( @new > 1 ){ foreach my $xxx (@new){ print '@new = '.strftime('%Y-%m-%d', l +ocaltime($xxx))."\n"; } $col->update( { "host" => $host }, { '$set' => { "timestamp" => @new } }, { 'multiple' => 1, 'safe' => 1 } ) || die "$!";

The foreach loop above is just to show there is data in @new. That works :). The update fails. The documentation for MongoDB is a bit sparse. I assume my syntax is wrong. Alas, I cannot figure how.

Neil Watson
watson-wilson.ca


Comment on Re^6: MongoDB replacing an array
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Re^7: MongoDB replacing an array
by Mr. Muskrat (Abbot) on Aug 26, 2012 at 23:38 UTC

    I'm hoping that I can learn a bit about MongoDB from trying to help you. Is the update happening within the @cols foreach loop? How are you getting $col? $col = $db->$cols;?

    Based on your @new foreach print, it looks like you are storing multiple timestamps in each record. Is that what you intended? If so, it seems odd to me to store timestamps in a column named timestamp. :)

      Yes, I am getting $col as you describe. No issue there. Yes, multiple timestamps in a record. This is what I intend.

      Neil Watson
      watson-wilson.ca

        Perhaps my short example script that seems to be working will help shed some light on what's wrong with yours? At the very least, I've gotten a little exposure to MongoDB out of this experience.

        #!/bin/env perl use strict; use warnings; use Data::Dumper; use MongoDB; use Try::Tiny; my $conn; # the connection can fail try { $conn = MongoDB::Connection->new; } catch { chomp( my $err = $_ ); $err =~ s/ at .*//; die "Unable to connect to the default MongoDB ($err)"; }; my $db = $conn->mydb; # shouldn't ever die because MongoDB will create + it if it doesn't exist my $hosts = $db->hosts; # ditto $hosts->insert({host => "127.0.0.1", timestamp => [ qw( 20110101 20110 +202 20110303 ) ]}); $hosts->insert({host => "127.0.0.2", timestamp => [ qw( 20110101 20110 +202 20110303 ) ]}); $hosts->insert({host => "127.0.0.3", timestamp => [ qw( 20110707 20110 +808 20110909 ) ]}); $hosts->insert({host => "127.0.0.1", timestamp => [ qw( 20111010 20111 +111 20111212 ) ]}); $hosts->insert({host => "127.0.0.2", timestamp => [ qw( 20110404 20110 +505 20110606 ) ]}); my $all_hosts = $hosts->find; my $ts; while ( my $host = $all_hosts->next ) { push @{$ts->{$host->{host}}}, @{$host->{timestamp}}; } # add non-existant host just to try and get an exception $ts->{'127.0.0.4'} = [ qw( 20120606 ) ]; $all_hosts->reset; for my $host ( keys %$ts ) { print "Updating $host..."; my @new = @{ $ts->{$host} }; # I wasn't able to get it to die even when trying to update a non- +existant record # $rc->{updatedExisting} will contain a true/false value but $rc-> +{err} is always undef # but I feel better trying to catch the croak my $rc; try { $rc = $hosts->update( { host => $host }, { '$set' => { timestamp => [ @new ] } }, { multiple => 1, safe => 1 } ); } catch { warn sprintf( "Couldn't update records for host %s, %s", $host +, $_ ); }; print $rc->{updatedExisting} ? 'success' : 'failure', "\n"; } while ( my $host = $all_hosts->next ) { printf "%s => %s\n", $host->{host}, Dumper( $host->{timestamp} ); } $hosts->drop; $db->drop;

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