String Translation

Hi All,

I have an upgrade script for the forthcoming version of Bricolage. It
has a function that looks like this:

sub update_all {
my ($table) = @_;
my $get_name = prepare("SELECT name FROM $table");
my $set_key_name = prepare("UPDATE $table SET key_name=? WHERE
name=?");

my $name;
execute($get_name);
bind_columns($get_name, \$name);

while (fetch($get_name)) {
my $key_name = lc($name);
$key_name =~ y/a-z0-9/_/cs;
execute($set_key_name, $key_name, $name);
}
}

Now, this is all well and good, except that it takes _forever_ to run!
I have it running now on a database with two tables to be updated, with
a total of 2213 rows, and it has been running for about 30 mins. And
yes, it's a fast server with a reasonably tuned database.

Now, I could speed this up if it could just run in a single query,
rather than with a big select and 2213 UPDATEs. The trouble is, I don't
know of an SQL equivalent to y/a-z0-9/_/cs, which translates any non
alphanumeric characters to underscores. I see that there's a
substring() function that supports POSIX regular expressions, but that
doesn't do a substitution.

So my question is, does anyone know of a way I could do this in the
database (and it is a one-time change [I hope!])? And if there is one,
will it be faster?

Many TIA,

David

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David Wheeler AIM: dwTheory
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