Database handle with perl always undefined

Question

I am having issues getting a simple DBI connection using perl to work.

I put a place checker to see if the database handle is undefined and it always comes out undefined. Are there any blatant errors? I'm assured that the info I enter is correct, as I'm using it in a php script.

#!/usr/bin/perl -w
use warnings;
print "Content-Type: text/html\n\n";

use DBI;

# Connecting to the database
# Replace DATABASENAME with the name of the database,
# HOSTNAME with the hostname/ip address of the MySQL server.
$drh = DBI->install_driver("mysql");
$dsn =   "DBI:mysql:database=db_name;host=host_name";
$dbh = DBI->connect($dsn,"username","password");
if(defined $dbh)
{
    print "Yes<br />";
}
else
{
    print "No<br />";
 }

 # Select the data and display to the browser

   $sth = $dbh->prepare("SELECT * FROM customer");
   $sth->execute();
   while (my $ref = $sth->fetchrow_hashref()) {
   print "Found a row: id = $ref->{'cid'}";
}

$sth->finish();

# Disconnect from the database.

$dbh->disconnect();

What happens if you connect() with { RaiseError => 1 } ? — pilcrow
– pilcrow, Commented Aug 23, 2012 at 20:23

ikegami · Accepted Answer · 2012-08-23 20:24:59Z

6

An error occured if connect returned undef. Throw some error handling in there. It might give you some useful information.

$dbh = DBI->connect($dsn, $user, $pw)
   or die "Unable to connect: $DBI::errstr\n";

edited Aug 23, 2012 at 20:24

ikegami

391k17 gold badges291 silver badges555 bronze badges

answered Aug 23, 2012 at 20:23

jmcneirney

1,3848 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

user1620902 Over a year ago

When I add the following or die to the code it does not print the statement afterwards? I have feeling something is messed up with perl, but wouldn't know where to start. $dbh = DBI->connect($dsn,"username","pw") or die "Unable to connect: $DBI::errstr\n"; print "why";

jmcneirney Over a year ago

It's unlikely that the problem is with perl. Can you manually connect to the database? Are all you parameters you're sending correct? Add a 'use strict' to your code too.

jmcneirney Over a year ago

I ran your code, with the added 'die' statement, on my machine and received an error.

user1620902 Over a year ago

The use strict helped determine the issue. It turns out it was evaluating part of the variables in the database handle and making those single quotes prevented that! Thanks!

jmcneirney Over a year ago

Great. You should always use 'use strict'. It will save you a lot of headaches.

Collectives™ on Stack Overflow

Database handle with perl always undefined

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related