Hey Monks,

I asked the question below at a mysql forum but didn't get any replies. So I'm trying my luck here - at the risk of being down-voted.

The code below checks for the existence of a username. If one already exists, the user is informed to choose another one. 

sub check_exist {
  $username = shift;
  # do the necessary dbi conection...
  $sql = qq{ SELECT * FROM $table{'members'} WHERE nick="$username"};
  $sth = $dbh->prepare($sql);
  my $result = $sth->execute()
    or bail_out("Cannot execute query.");
  $dbh->disconnect();
  if ($result eq '0E0') {
    return $username;
  }
  else {
    bail_out("$username has already been taken...");
  }
}

[download]
What I'm not so certain is the test for existence part. What's the right way to test for the existence (or non-existence) of a particular query string?

Updated:Thanks to Zaxo, mpeppler and CountZero! I implemented UNIQUE INDEX on the username and that itself prevents duplicate names. As a result, the check_exist sub has become redundant - but it was good for learning purposes. I don't think the book teaches you all this stuff!

In reply to perl (mysql) question... by kiat

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