On 25.05.2010 14:21, Larry W. Virden wrote:
$drc = $handle->prepare ("DELETE FROM MyTable WHERE EMPNO = ?") or
do {
print "DELETE prepare failed - $DBI::errstr\n";
next;
}
$drc = $oraProdDBH->execute ($employee) or do {
print "DELETE execute for $employee failed - $DBI::errstr\n";
next;
}
if ($drc != 1) {
if ($drc eq '0E0' or $drc == 0) {
print "DELETE from MyTable for EMPNO $employee changed
0 rows\n";
} else {
print "DELETE from MyTable for EMPNO $employee changed
$drc rows\n";
}
}
I really recommend that you set the RaiseError attribute to 1 when
calling DBI->connect(), and that you read the fine manual (i.e. the DBI
documentation).
Both together will make your code shorter and easier to read. Wrap code
that may fail into an eval { ... }, check $@ afterwards, i.e.
my $dbh=DBI->connect('dbi:Oracle:ORCL','scott','tiger',{ RaiseError =>
1, PrintError => 0, AutoCommit => 1 });
eval {
my $sth=$dbh->prepare(...);
$sth->execute(...);
while (my $row=$sth->fetchrow_hashref('NAME_uc')) {
...
}
$sth->finish();
};
if ($@) {
print "Something went wrong: $...@\n";
} else {
print "Oh happyness, everything is well\n";
}
Or for a simple $dbh->do(...):
my $dbh=DBI->connect('dbi:Oracle:ORCL','scott','tiger',{ RaiseError =>
1, PrintError => 0, AutoCommit => 1 });
eval {
if ($dbh->do('DELETE ...',...)>1) { # $dbh->do() will never return
undef, due to RaiseError. It will die() when it fails.
die "Rats, killed too many records"; # escape the eval block
}
};
if ($@) {
print "Something went wrong: $...@\n";
} else {
print "Oh happyness, everything is well\n";
}
Even better, with transactions:
my $dbh=DBI->connect('dbi:Oracle:ORCL','scott','tiger',{ RaiseError =>
1, PrintError => 0, AutoCommit => 1 });
eval {
$dbh->begin_work();
$dbh->do($this);
$dbh->do($that);
if ($dbh->do('DELETE ...',...)>1) { # $dbh->do() will never return
undef, due to RaiseError. It will die() when it fails.
die "Rats, would have killed too many records"; # escape the eval
block, avoid the commit and force a rollback
}
$dbh->commit(); # commit may fail, in that case, you also want a
rollback
};
if ($@) {
warn "Rolling back because an error occured: $@";
$dbh->rollback(); # may die if even rollback failed, I consider this
a good thing.
} else {
print "Oh happyness, everything is well\n";
}
And by the way: if ($drc eq '0E0' or $drc==0) is redundant, it would be
sufficient to use $drc==0 ('0E0' is 0, but unlike a "real" 0, it
evaluates as true in a boolean context).
Alexander
--
Alexander Foken
mailto:alexan...@foken.de http://www.foken.de/alexander/
