[EMAIL PROTECTED] [[EMAIL PROTECTED]] wrote:
> Hello Everyone,
>
> The code I'm including makes the line graph I want, except that no points are
> plotted. It comes out as an empty graph with only the 0 for elevation on the
> Y-axis label and the first date, 2001-01-01, on the X-axis label. I have
> absolutely no idea why. I've tried two methods for doing this, which I've
> marked in my code. I am a novice at this, so I'm sure my code could be
> *much* better. Please be merciful. :) -- Michelle
Michelle, I'm not familiar with the Chart tool, but a few comments
on your DBI code(see below). Are you sure your
1. connect is working
2. select is working, and finding the right rows
>
> Here's my code:
>
> #! /usr/bin/perl -wT
>
> use DBI;
> use CGI::Carp qw(fatalsToBrowser);
>
> ### variables to count results ###
> $xcount = 0;
> $ycount = 0;
>
> ### connect to my database ###
> $dbh = DBI->connect("DBI:mysql:mydatabase", "username", "password") ||
> die $DBI::errstr;
Try turning on RaiseError to help catch DBI errors - change your
connect:
$dbh = DBI->connect("DBI:mysql:mydatabase",
"username",
"password",
{ RaiseError => 1, PrintError => 0, AutoCommit => 1 }
) || die "Connect failed: $DBI::errstr";
>
> ### form sql statement ###
> $graphsql = "SELECT loc_id, elevation, date FROM mrddaily
> WHERE loc_id = 1 AND date <= 20010105 AND date >= 20010101";
>
> ### prepare and execute query ###
> $sth = $dbh->prepare($graphsql);
> $sth->execute();
>
> ### store query results ###
> while (@ary = $sth->fetchrow_array()) {
> if (@ary[0] == 1) {
> push (@y, @ary[1]);
> $ycount++;
> push (@x, @ary[2]);
> $xcount++;
> }
> }
>
> ### make DBD::Chart object ###
> $dbh = DBI->connect('dbi:Chart:') || die "Cannot connect\n";
>
> ### create table to hold values ###
> $dbh->do('CREATE TABLE line (date DATE, elevation FLOAT)');
>
> ### add data to be plotted ###
> $sth = $dbh->prepare('INSERT INTO line VALUES( ?, ?)');
>
> ################## first failed method ##################
> # (I know this one puts the values in the table because I checked it in
> mySQL)
> #for ($i=0, $j=0; $i<$xcount, $j<$ycount; $i++, $j++) {
> # $sth->execute(@x[$i], @y[$j]);
> #}
> #########################################################
>
> ################# second failed method ##################
> # (I don't really understand this one,
> # but it looked like what I needed in the example)
> $sth->func(1, \@x, chart_bind_param_array);
> $sth->func(2, \@y, chart_bind_param_array);
>
> %stsary = ();
> $sth->func(\%stsary, chart_bind_param_status);
> #########################################################
>
> $sth->execute;
>
> ### render chart ###
> $rsth = $dbh->prepare("SELECT LINEGRAPH FROM line
> WHERE WIDTH=600
> AND HEIGHT=400
> AND X-AXIS=\'Date\'
> AND Y-AXIS=\'Elevation\'
> AND TITLE=\'Choke Canyon Elevation\'
> AND COLOR=(red)
> AND SHOWPOINTS=1
> AND SHOWGRID=1
> AND SHAPE=(fillcircle)
> AND BACKGROUND=lgray
> AND X-ORIENT=\'VERTICAL\'");
> $rsth->execute;
> $rsth->bind_col(1,\$buf);
> $rsth->fetch;
>
> ### output chart to browser ###
> print "Content-type: img/png\n\n";
> print "$buf";
>
--
Hardy Merrill
Mission Critical Linux, Inc.
http://www.missioncriticallinux.com
