Mike Blezien [EMAIL PROTECTED] wrote:
> Hardy,
>
> thx's I think this maybe exactly what we were looking for,
> but currently do not utilize transactions in our coding. Is
> there another preferred way to do about the same thing
> without using transactions ??
Mike, you can still use the same logic, even if you
don't utilize transactions - your code might look like
this:
$dbh->{AutoCommit} = 0; # enable transactions, if possible
$dbh->{RaiseError} = 1;
eval {
foo(...) # do lots of work here
bar(...) # including inserts
baz(...) # and updates
};
if ($@) {
warn "Problem with foo, bar, or baz: $@";
# add other application on-error-clean-up code here
}
Another thing you can do which I have done before is to do
your own dies in an eval - that will cause the $@ variable
to be populated with the error message. So you could do
something like this:
eval {
my $sth = $dbh->prepare(qq{
UPDATE foo
SET name = ?,
phone = ?
WHERE id = ?
}) || die "Prepare failed: $DBI::errstr";
$sth->execute($name, $phone, $id)
|| die "Execute failed: $DBI::errstr";
};
if ($@) {
warn "Problem with UPDATE: $@";
# add other application on-error-clean-up code here
}
But this is more work, and really yields about the same
thing anyway - my preference is to use the first method
(with RaiseError=1). Read the perldocs on RaiseError.
HTH.
--
Hardy Merrill
Red Hat, Inc.
>
> thx's
> --
> Mike<mickalo>Blezien
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>
>
> Hardy Merrill wrote:
> >Mike Blezien [EMAIL PROTECTED] wrote:
> >
> >>Hi,
> >>
> >>we have a small automatied billing system, written in perl
> >>using DBI to access our MySQL database. This system utilizes
> >>various control panels for customer, webmasters,...etc...
> >>where they log in to perform various functions, submit
> >>forms,..etc.. alot of activity with our MySQL db.
> >>
> >>what we'd like to do, is when there is any type of a
> >>database error, connection, queries,..etc,.. is then
> >>'trapped' the error for later review, if needed, and display
> >>in the browser at the time of the error, a simple error
> >>messages to indicate there was a problem encoutered, nothing
> >>specific, then log the DBI error on the server for review.
> >>
> >>would it be best to log in each error to a file, using
> >>something like:
> >>
> >>if ($DBI::errstr) { $err_mesg = $DBI::errstr };
> >>
> >>then write this to a separate error logfile ??
> >>
> >>and is it best to set the PrintError=1 & RasieError=1 for
> >>this type of procedure ??
> >>
> >>appreciate any suggestions or tips,
> >
> >
> >Here's my take - I do pretty much exactly what the
> >DBI perldocs ('perldoc DBI' at a command prompt) suggest
> >for error handling using 'eval' and Transactions. Here's
> >a snippet from the DBI perldocs on 'Transactions':
> >
> > The recommended way to implement robust transactions in Perl
> > applica-
> > tions is to use "RaiseError" and "eval { ... }" (which is very fast,
> > unlike "eval "...""). For example:
> >
> > $dbh->{AutoCommit} = 0; # enable transactions, if possible
> > $dbh->{RaiseError} = 1;
> > eval {
> > foo(...) # do lots of work here
> > bar(...) # including inserts
> > baz(...) # and updates
> > $dbh->commit; # commit the changes if we get this far
> > };
> > if ($@) {
> > warn "Transaction aborted because $@";
> > $dbh->rollback; # undo the incomplete changes
> > # add other application on-error-clean-up code here
> > }
> >
> >If any errors occur in the eval, the RaiseError will cause
> >a die and the $@ variable will be populated with the error
> >message. So, in the 'if ($@) {' block, you can do whatever
> >you want to - where it says 'warn...', if you want to display
> >some generic error message you can do that, and if you want
> >to log the error you can do that too. I typically log errors
> >to the webserver(apache) error log by printing errors to
> >STDERR, which is exactly what 'warn' does above.
> >
> >HTH.
