I'm going mad...
I've searched the MySQL docs, I've searched the DBI mailing list for over
an hour, and all I get back is SQL strings, which I understand all too
well but what I really need is code snippets of examples, and I can't find
any at all...
I would expect that this would be enough:
$querycount = "SELECT COUNT(*) FROM povbench where no_processors=1";
$rv = $dbh->do( $querycount );
It just returns "1", presumably indicating that it was successful, but how
can I find the actual magic number? I just couldn't find an example
anywhere.
I don't know whether it returns a count value, or an array which has to be
fetched or whether $dbh-->do or $dbh->prepare with $dbh->execute is the
correct method.
I even installed MySQL on my NT system and added Perl::DBI and got it
working within 2 minutes. Created an identical table to that on the linux
server and running identical perl code on NT as on Linux. I'm pleased with
myself that I did this much in such a short time, but it's taken me just
as long to get nowhere looking for help on how to get a damn result from
using COUNT!!! Maybe I should lie down for a while...
I run the povbench database on www.haveland.com/povbench and it's
currently grown to a flat file db of over 1500 records and under stress.
I'm converting it to MySQL on Linux as I thought it would be an easy
exercise and I had it working after 2 hours, generating a nice pretty
multicoloured table, but I just iterate through the tables and display
those records that are between the variable $from and ($from+20). Messy...
You can see what I did on www.haveland.com/cgi-bin/show.cgi
Just needs to go backwards and not display one of the prev or next
controls if at the end or the beginning of the record set.
I want to deliver paginated output, eg: Results [1-50], [51-100], like
we're used to with the search engines, and would like some guidance and
code examples on the best method.
I'll work on user submissions once I got the output working the way I want
it, and then finally get round to doing a much more demanding benchmark.
I really don't want to have to read everything into an array and then
slice it. I've gathered that COUNT and LIMIT are there for that, but how
do I use them in practice in plain perlesque English?
Once I've cracked this, my next project is to convert a complicated but
small relational Access DB with 40 or so tables in it to MySQL and use XML
cos I think it could be fun, and because I will have to in the near future
for a contract I'm working on...
Any help gratefully appreciated!
Cheers,
Andy.
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Haveland-Robinson Associates Tel. +36 30 223 2158
Budapest 1015, Donáti u.17 fszt.1, Hungary Web: www.haveland.com
