Samn has asked for the wisdom of the Perl Monks concerning the following question:

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•Re: Hash from DBI
by merlyn (Sage) on Apr 30, 2003 at 09:32 UTC
    Maybe I'm being dense this morning but won't this do it: 
    while (my $ret = $sth->fetchrow_hashref) {
  my %user = %$ret;
  ...
}

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    Although I would argue that your code is making an unnecessary copy of an unnecessary copy. So hopefully you aren't optimizing for performance... just programmer flexibility.

    -- Randal L. Schwartz, Perl hacker
    Be sure to read my standard disclaimer if this is a reply.

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      Or even more directly 
      while (my %user = %{ $sth->fetchrow_hashref }) {
  ...
}

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      HTH

      _________
      broquaint

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Re: Hash from DBI
by nite_man (Deacon) on Apr 30, 2003 at 11:11 UTC
    I would like to suggest you retrive all rows of query execute result for one time: 
    use DBI;

. . .

my $res = $sth->fetchall_arrayref(); # Returns array ref with all resu
+lt rows which are array refs too.
for my $row (@$res) {
    for my $value (@$row) { print "$value " }
    print "\n";
}

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    or 
    my $res = $sth->fetchall_arrayref({}); # Returns array ref with result
+ rows which are hash refs.

for my $row (@$res) {
    for my $key (%$row) { print "$$row{$key} " }
    print "\n"; 
}

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--------------------------------
SV* sv_bless(SV* sv, HV* stash);
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Re: Hash from DBI
by hmerrill (Friar) on Apr 30, 2003 at 14:20 UTC
    Why not do something like this: 
      while ($user_hashref = $sth->fetchrow_hashref) {
     print "name = $user_hashref->{username}\n";
     print "email = $user_hashref->{email}\n";
  }

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    The hashref that fetchrow_hashref gives you back doesn't necessarily need to be turned back into another hash to be used - you can use the hashref($user_hashref above) to point at individual element values using the greater than(->) notation.

    HTH.
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Re: Hash from DBI
by gmpassos (Priest) on May 01, 2003 at 04:02 UTC
    Well, this isn't really a DBI question.

    First you can use the hash reference inside of the scalar very similar to a normal hash, just use $$hash{foo}: 

      my $hash_ref = {
  a => 1 ,
  b => 2 ,  
  } ;
  
  print "$$hash_ref{a}\n" ;
  print "$$hash_ref{b}\n" ;

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    But if you really want to use $hash{foo} directly, without make a copy, use this code: 

      my $hash_ref = {
  a => 1 ,
  b => 2 ,  
  } ;
  
  local(*hash) ;
  *hash = $hash_ref ;

  print "$hash{a}\n" ;
  print "$hash{b}\n" ;

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    But note that %hash is declared inside *hash, with local() to simulate the my %hash! And any other variable or handle with the name hash will be overwrited. In other words, local() works for: $hash, @hash, %hash, hash

    Graciliano M. P.
    "The creativity is the expression of the liberty".

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