in reply to Pearls (not really) of Perl programming

One of mine, in the early days of learning about DBI... 

open INFILE, '<source.txt';

while (<INFILE>) {
   my $dbh = DBI->connect("dbi:mysql:database=maindb;host=localhost");
   my $sth = $dbh->prepare("SELECT * FROM $table WHERE uid=$user");
   $sth->execute;
   print join(',', $sth->fetchrow_array);
   print "\n";
}

[download]

Note the complete lack of error handling, no use of prototypes, and the assumption that only one row would be returned. I also particularly enjoy the two separate print statements. And, I printed to STDOUT (without setting $|) even though I wanted to write to a file.

radiantmatrix
require General::Disclaimer;
Perl is

Replies are listed 'Best First'.
Re^2: Pearls (not really) of Perl programming
by hubb0r (Pilgrim) on Nov 25, 2004 at 07:00 UTC
    Plus, depending on the number of lines in the INFILE, you probably swamped the DB by not keeping the $dbh outside of the while.
[reply]

      Quite. Not to mention that particular app connected to a mysql instance that was about 5 router hops away over not-the-fastests links. Connect times averaged 5s, which really reared its ugly head when the input file was 2_000 lines. ;-)

      radiantmatrix
      require General::Disclaimer;
      Perl is
[reply]
Re^2: Pearls (not really) of Perl programming
by ihb (Deacon) on Nov 26, 2004 at 02:17 UTC

    Also, there's no localization of the filehandle.

    ihb

    See perltoc if you don't know which perldoc to read!
    Read argumentation in its context!

[reply]
[d/l]
Re^2: Pearls (not really) of Perl programming
by Mr. Muskrat (Canon) on Dec 04, 2004 at 04:05 UTC

    I could probably write a book on the subject of the OP but I'll stick to just one DBI example.

    my $dbh = DBI->connect($database, $user, $password) or die $dbh->errstr;

    When I found it, I decided to grep for it. It was being used in every script that pulled from the database!

[reply]
[d/l]

In Section Meditations