in reply to Re^2: Capturing error thrown by a database
in thread Capturing error thrown by a database

When the DBI has an error, it is available as the string provided by DBI->errstr. So for example in a wild guess at your subroutine below, if the connection fails (no handle returned), the sub returns the DBI->errstr. Of course your calling program would have to do something with that. PrintError=1 causes warning message to be printed, you may or may not want that. RaiseError=1 is a bit stronger and causes a "die", which you don't want unless you inside of a block eval.

You can set RaiseError =1 and put statements in an eval{} which in this context would be Perl's equivalent of a try/catch. In the case of failure, again, calling the errstr method of the DBI will give you its error. 

my $dbh;

sub connectsybase
{
   my ($var1, $var2,...) = @_;

   $dbh = DBI->connect($data_source, $username, $auth,
          {printError => 1} );
   return (DBI->errstr) if (!dbh);    # fail
   return "";                         # success, NULL string
}

[download]

Replies are listed 'Best First'.
Re^4: Capturing error thrown by a database
by puneet.keswani (Novice) on Aug 01, 2011 at 12:53 UTC
    Hi Marshall.. The example which you have given is working fine.. i am extremely thankfull to you for that, but I am using the RaiseError=1 attribute, which causes a die, inside an eval.. Can you give an example similar to above using RaiseError=1.. Thanks a lot..
[reply]
      You just check and see if $@ gets set after the eval block. See eval doc page

      eval 
{
   some db command
   $dbh->do....;
}
if ($@)
{
   print "$@\n";
   print $DBI::Errstr,"\n";
}

      [download]
      do some experimenting, $@ may be same as the dbi's error string if PrintError =1.
[reply]
[d/l]
        Hey Marshall.. I have already tried that.. I am pasting here the code snippet. Please advise.. eval { sub OpenSybaseConnection { my ($srv, $user, $pwd, $db) = @_; my $dbh; $FH1=$_4; print $FH1 "\n\nConnected to Server:$srv, Database:$db\n"; $dbh=DBI->connect("dbi:Sybase:server=$srv", $user, $pwd,{RaiseError =>1,PrintError =>1 }) || die $DBI::errstr; $dbh->do("use $db"); $common::conn_hdl = $dbh; }; }; if($@) { @proc_error=$@ ; print "inside if\n"; print "Check for if\n"; print "Hi:$@"; print "\nIn Common: @proc_error: HELP"; }
[reply]

In Section Seekers of Perl Wisdom