Can't call method "do" - DBI Troubles

[vbrtrmn]

Hey, I'm having some probs w/ DBI today. My code bombs with:

Can't call method "do" on an undefined value at /var/www/html/sites/www.auroraborealis.org/cgi-bin/gbdbconnect.cgi line 19.

Here's my code:

#!/usr/bin/perl -w

use strict;
use DBI;
use CGI::Carp "fatalsToBrowser";
use CGI ":all";

my $username = 'USERNAME';
my $pass = 'PASSWORD';

my $db = 'DBI:mysql:auroraborealis:localhost';
my $db_object = DBI->connect($db, $username, $pass);


print header();
print "<PRE>";

my $sql = "SELECT * FROM guestbook ORDER BY name";
my $dbh->do($sql);
$dbh->disconnect();

exit;

--
paul

[broquaint]

Change your database assignment line to

my $dbh = DBI->connect($db, $username, $pass);

And the line with do on it to

$dbh->do($sql);

You'll also probably want to check the return of both of those statements in case they fail.
HTH

_________
broquaint

[robartes]

To expand on broquaint's perfectly correct answer:

The reason your code is not working is because you first assign the reference to the DBI object (commonly called the Database handle, hence $dbh) to db_object:

my $db_object = DBI->connect($db, $username, $pass);

after which you try to access it through a new variable $dbh, which is of course undefined:

my $dbh->do($sql);

hence the error. I suspect that you put in the my because the compiler complained about a missing package name on $dbh. You need to drop the my.

CU
Robartes-

[Cabrion]

Adding one more suggestion to this list of correct answers, you should probably trap some errors with . . .

my $dbh = DBI->connect($db, $username, $pass) || die $DBI->errstr();

and

my $dbh->do($sql) || die $dbh->errstr();

to catch any underlying problems with the connection process or underlying SQL execution.

[Hero Zzyzzx]

You can use the RaiseError option in the connect() method to automatically "status check" all calls to database functions, a nice little time saver. Note: you still have to status check the connect() method itself. . .

my $dbh=DBI->connect($db,$username,$pass,{RaiseError => 1}) or die("Co
+uldn't connect to database ".DBI::errstr);

and the statement

$dbh->do($sql);

will automatically have status checking done for it, as well as any other calls to DBI.

-Any sufficiently advanced technology is
indistinguishable from doubletalk.

[electrosphere]

Perl is asking you to look hard at line 19...

You must run the 'do' on a defined database handle. The database handle is ruturned by the DBI->connect method. In your code this handle is stored in $db_object (I think $dbh would be a better identifier - database Handle).

Change line 19 to: $db_object->do($sql);

I think you want to use the prepare/execute methods when working with SQL Selects as the do method does not return a statement handle (see perldoc DBI for more info)