Hi Monks,

I've just written my first (significant) package, which is intended to centralise connections to a database, and the running of queries against it.

Here's script1.pl, which is the first of several scripts which will call the package:

#!/usr/bin/perl

use crsTools4;

connect2db;

# Test query using $sth
run_sql("SELECT * FROM person WHERE firstname = 'Joe'");
while ((@f) = $sth->fetchrow())
{ print "@f\n" }

# Test query using $sth2 (though I could just reuse $sth in this case)
run_sql("SELECT * FROM person WHERE firstname = ? AND surname = ?",2,'
+Joe','Bloggs');
# while ((@f) = $sth2->fetchrow())
while ((@f) = $sth->fetchrow())
{ print "@f\n" }

[download]

And here's the package (filename crsTools4.pm):

package crsTools4;

require Exporter;
our @ISA    = qw(Exporter);
our @EXPORT = qw(connect2db run_sql); # Symbols to be exported by defa
+ult
our @EXPORT_OK  = qw($dbh $sth);

sub connect2db
{
        require DBI;
        our $dbh = DBI->connect("DBI:mysql:database=crs;host=127.0.0.1
+", 'crs_user', 'mypw') or die('Could not connect!');
}

# Execute an SQL command (arg 1), with an optional specified handle #
# (arg 2), and optional bind variables (args 3...).
sub run_sql
{
        my ($sql, $n) = (shift @_, shift @_);
        print "sql=\"$sql\", sth$n, bind=\"" . join(',',@_) . "\"\n";
        # $$sth = $dbh->prepare($sql);
        # $$sth->execute(@_) or die "Could not execute: $DBI::errstr\n
+";
        # To make things simple while debugging, let's just hard-code 
+$sth
        $sth = $dbh->prepare($sql);
        $sth->execute or die "Could not execute: $DBI::errstr\n";
}

1;  # Required for all packages, to return a true value

[download]

And, here's the output, complete with error message:

sql="SELECT * FROM person WHERE firstname = 'Joe'", sth, bind=""
Can't call method "fetchrow" on an undefined value at ./test4.pl line 
+9.

[download]

As you can see, it fell over on the first query.  Any ideas what I'm doing wrong?  I assume it's to do with localisation of $sth or something (though I tried to make it global), but after a lot of trial and error, I'm ready to take advice from the experts...please.

Thanks.

In reply to Errors from a simple Package by tel2

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