Link to home
Start Free TrialLog in
Avatar of slok
slok

asked on

CGI and DBI "cache' problem?

I got the following CGI program which takes in one field 's_off_no' from a query from.

Problem is it only works one time and after that, even though I am submitting different queries values, it is still using the very first value to do the database queries.

any suggestions?


=============================================

do 'dbi-lib.pl';



use CGI ':standard';
use DBI;
use strict;
use vars qw($baseURL);

# Declare base URL for return from this page
$baseURL = "../index.html";

 my $q = new CGI;
 my $user = $q->param('user');
 my $passwd = $q->param('passwd');
 my $action = $q->param('action');
 my $s_off_no = $q->param('s_off_no');


printHead('TDPS - Delete Offence');

# check that user is logon
if (($user eq '') || ($passwd eq '')) {

  goLogon();
  return;
}


print EOM;
table border=0 cellpadding=0 cellspacing=0 width=100%>
tr>
td>
EOM

searchform();
queryresult($s_off_no);


print EOM;
hr>
EOM

print EOM;
/td>
/tr>
/table>
EOM

printclose();



sub searchform {
   
print EOM;

form action="query.pl" method="post">
input type="hidden" name="user" value="$user">
input type="hidden" name="passwd" value="$passwd">
table border="0" cellpadding="2" cellspacing="2">
tr>
td colspan="2" class="pagetitle">Delete Offence Details/td>
/tr>
tr>
td>Offence Number/td>
td>input type="text" name="s_off_no" size="5" maxlength="5"> input type="submit" value="Search">/td>
/tr>
/table>
/form>

EOM


}



sub queryresult {

#my $s_off_no = $s_off_no;
     my ($s_off_no) = @_;

     
     
    my $debug = 1; # 0 to off, 1 to turn it on        
    my $results;

    my $dbuser = '111';
    my $dbpasswd = '222';
   

       
    # Query to check if driver exist
    my $query1 = "select veh_reg_no from offence " .
                 "where off_no = $s_off_no";    

    # Database DBI driver name
    my $dbname = "DBI:Oracle:";

    # Create database handle
    my $dbh = DBI->connect($dbname, $dbuser, $dbpasswd);
    if (!$dbh) {
       showSQLerror("Connecting to the database");
       return;
    } else {
      # set AutoCommit  1 = ON, 0 = OFF (1 is default)
      # transaction control is *required* here, hence set OFF
      $dbh->{AutoCommit} = 0;
    }

    if ($debug == 1) {
      print("
query1: $query1");    
    }
    $results = run_statement($dbh,$query1,"Y");
    if ($results == 0) {
        printErrors('Invalid Offence No.!');
        return;
    } elsif ($results == -1) {
        $dbh->rollback;
        $dbh->disconnect;
        return;
    } else {
   
      $dbh->commit;
      $dbh->disconnect;
      print("
$results");
    }
}


sub run_statement {

    my ($dbh,$sql,$getNo)=@_;
    my $new_offNo;

    # Create a statement handle - prepare the statement
    my $sth = $dbh->prepare($sql);
    if (!$sth) {
        showSQLerror("Preparing SQL statement");
        return (-1);
    }

    # Execute the statement against the database
    $sth->execute;
    if ($DBI::errstr) {
        showSQLerror("Executing SQL Statment");
        $sth->finish;
        return (-1);
    }

    if ($getNo eq "Y") {
        ($new_offNo) = $sth->fetchrow;
    } else {
        $new_offNo = 0;
    }
    $sth->finish;

    return ($new_offNo);
}
=============
Avatar of oleber
oleber
Flag of Portugal image



sub searchform {
 
my $time=time();  
print EOM;

form action="query.pl" method="post">
input type="hidden" name="user" value="$user">
input type="hidden" name="passwd" value="$passwd">

input type="hidden" name="stupid_value" value="$time">

table border="0" cellpadding="2" cellspacing="2">
tr>
td colspan="2" class="pagetitle">Delete Offence Details/td>
/tr>
tr>
td>Offence Number/td>
td>input type="text" name="s_off_no" size="5" maxlength="5"> input type="submit" value="Search">/td>
/tr>
/table>
/form>

EOM


}
Avatar of slok
slok

ASKER

well, I print out the "stupid_value" everytime I submit the query from the form. And the time is different.

But my database query is still using the first "query" parameter.

Probably I cann't help you. I see the code and i didn't understand the why of your problem.

Did you try the GET method in the form?


Avatar of slok

ASKER

I manage to solve the problem. though I don't know why.

By moving codes like
==
my $q = new CGI;
my $user = $q->param('user');
my $passwd = $q->param('passwd');
my $action = $q->param('action');
my $s_off_no = $q->param('s_off_no');
==

and any other validation code into subroutine, it solves the problem with 'caching'. Not sure why if these codes exist in the "main", it will have a 'caching' effect.

I will delete this question in a week's time.

Thanks for the help.
what is your server? are you using mod-perl, mason, ... or something like that?
Avatar of slok

ASKER

I'm running Apache 1.3.19 with mod_perl on win2k.
Perl used is ActivePerl.
ASKER CERTIFIED SOLUTION
Avatar of oleber
oleber
Flag of Portugal image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Avatar of slok

ASKER

I probably would not go and test your sample codes.
But the proposed solution makes sense.

Will accept it as others might find it useful.

Thanks a lot for all the help. Definitely a learning experience.