Accessing Pervasive.SQL With Perl

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DBI + ODBC - Fetching Examples 4 - catching errors using the code

use strict;
use warnings;
use DBI;

print "Connecting to database...\n";
my $dbHandle = DBI->connect('dbi:ODBC:DEMODATA', '', '', {PrintError=>0, RaiseError=>0});

if(defined($dbHandle))
{
   print "Preparing query...\n";
   my $stHandle = $dbHandle->prepare('SELECT Name,Description FROM Course ORDER By Name');
   if(defined($stHandle))
   {
      print "Running query...\n";      
      my $ret = $stHandle->execute();
   
      if(defined($ret))
      {
         print "Returning rows...\n";
         while(my @returnRow = $stHandle->fetchrow_array())
         {
            print "Name: $returnRow[0], description: $returnRow[1]\n";
         }
      }
      else
      {
         print "Unable to run query\n";	      
      }
      
      $stHandle->finish();
   }
   else
   {
      print "Unable to create statement\n";
   }

   print "Disconnecting...\n";      
   $dbHandle->disconnect();
}
else
{
   print "Unable to create database handle\n";
}

print "Finished\n";

Now we explicitly check each call and make sure that any allocated resources are freed. We have to create our own error messages, which hopefully are a bit more detailed than this example, e.g. using $DBI::err and $DBI::errstr, and there is the risk of not checking every call, such as the fetchrow_array in the example above where it is assumed that no return value means no more rows left.

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