Re: Re: Re: DESTROY and DBI

Hi Mike,
Yes, of course I bless my object.
I even tried this, but I think it is the same as during the exit.

my $o=new MyClass;
my $dbh=$o->opendb;
warn $o->{_dbh};
warn $dbh; # the same as the previous line
undef $o;
exit;
[download]

I cannot put it as a lexical in the sub because I have just written an entire framework (+5000 lines), consisting of a tree of packages in OO, and setting the DBI object as an attribute has an advantage of using persistant DB connections.

This is the actual opendb routine

sub opendb {
   my $self=shift;
   local($@);
   if ( not $self->{_dbh} or not $self->{_dbh}->ping) {
      eval{ $self->{_dbh}=$self->{_dbi}->connect() ; } ;
      if ( $@ ) {
         $self->Log('!',$@) and die "db gives error" ;
         }
      }
   $self->{_dbh}->{LongReadLen}=100000; # to handle Long column types
   $self->{_dbh}->{LongTruncOk}=0;   # generates an error when the dat
+a is too long
   $self->{_dbh}->{AutoCommit}=0;   # Lets run transactional
   return $self->{_dbh};
   }
[download]

And I call this opendb as much as I like, without going to the db everytime. (note $self->{_dbi} is a object from my superclass of DBI). And the link to tilly's one, that was the one I was referring to, but using flyweightwrapper is a bit overshooting, I think.
---------------------------
Dr. Mark Ceulemans
Senior Consultant
IT Masters, Belgium

Comment on Re: Re: Re: DESTROY and DBI Select or Download Code

Replies are listed 'Best First'.
Re^4: DESTROY and DBI by RMGir (Prior) on Aug 27, 2002 at 14:01 UTC
(Edit: I don't believe _dbh goes away before $self does, I think DBI is unloaded before the global cleanup happens; that's why I'm suggesting this END{} fix...) Hmmm, you don't need the total encapsulation features of the FlyweightWrapper, either... I'm betting packages get unloaded correctly. What happens if you add a hash at the package level in your class called instances, and do this: `# private hash of instances my %instances; #... sub new { # ... build up $self, bless it, do whatever $instances{$self}=1; # ... whatever else you need to do... } #... sub DESTROY { # don't double-destroy return unless $instances{$self}; #... do whatever $instances{$self}=0; } END { foreach my $instance(keys %instances) { $instance->DESTROY() if $instances{$instance}; } }` [download] Offhand, I can't remember whether calling DESTROY directly is ok or not, but if not, you could get the same effect with a helper sub that DESTROY calls. -- Mike Edit: I forgot to check $instances{$self} at the top of DESTROY	[reply] [d/l]

Replies are listed 'Best First'.

Re^4: DESTROY and DBI
by RMGir (Prior) on Aug 27, 2002 at 14:01 UTC

Edit:

Hmmm, you don't need the total encapsulation features of the FlyweightWrapper, either...

I'm betting packages get unloaded correctly. What happens if you add a hash at the package level in your class called instances, and do this:

# private hash of instances
my %instances;

#...
sub new {
    # ... build up $self, bless it, do whatever
    $instances{$self}=1;
    # ... whatever else you need to do...
}

#...
sub DESTROY {
    # don't double-destroy
    return unless $instances{$self};
    #... do whatever
    $instances{$self}=0;
}

END {
   foreach my $instance(keys %instances) {
       $instance->DESTROY() if $instances{$instance};
   }
}
[download]

Edit: I forgot to check $instances{$self} at the top of DESTROY

[reply]
[d/l]