You have:

use strict;
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which enabels strictures, see perldoc strict. You need to declare variables before using them, e.g. my $input;. Copying and pasting other peoples code without understanding it is a bad idea. Consider spending some time working your way through the following links:

• perlintro
• http://learn.perl.org
• http://perldoc.perl.org
• The tutorials section of this site, Use strict warnings and diagnostics or die, Debugging and Optimization

Update: Also, don't ignore previous advice. See the responses to Re^2: How to get input text boxes populated.

if ( ($action eq "UPDATE") && ($empid =~ /\d+/)) {

  my @data=();
  my @fields = qw!lastname firstname title toc dob doh address city
                  region pcode country homephone ext notes repto!;
  for my $f (@fields)[
    push @data,$q->param($f) || '' ;
  }  
  push @data,$empid;
                  
  my $sql = qq!UPDATE "Employees" 
               SET "LastName"  = ?,
                   "FirstName" = ?,    
                   "Title"     = ?,          
                   "TitleOfCourtesy" = ?, 
                   "BirthDate" = ?,
                   "HireDate"  = ?, 
                   "Address"   = ?, 
                   "City"      = ?,    
                   "Region"     = ?,            
                   "PostalCode" = ?,            
                   "Country"    = ?,             
                   "HomePhone"  = ?,   
                   "Extension"  = ?,            
                   "Notes"      = ?,           
                   "ReportsTo"  = ?           
             WHERE "EmployeeID" = ? !;
               
  my $count = $dbh->do( $sql,undef,@data);
  $msg = "$count Record updated - $sql, @data";
} else {
  $msg = "Please complete form";
}
[download]

"still the same, still its not executing the update query, no updates are being sent to the database and even worse no errors are being displayed. There's got to be something else"

It seems like a good time for you to start debugging this problem for yourself to find out what that "something else" is. Tutorials->Debugging and Optimization->Basic debugging checklist.

Update: Also, you're replying to yourself. Consider reading and understanding PerlMonks for the Absolute Beginner.

To understand why the update block is not being executed add a debug line into the else part.

} else {
  $msg = "Please complete form";
  $msg.= "<br/>Debug : action=[$action] empid=[$empid]";
}
[download]

You will have to change the regex $empid =~ /\d+/ in the if() to some other pattern if your EmployeeID's don't contain a number, or maybe just use $empid ne ''
poj

perl -MCarp::Always edit2.pl    
Use of uninitialized value $action in string eq at edit2.pl line 22 (#
+1)
[download]

Please complete form
Debug : action=[UPDATE] empid=[]
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If you write more subroutine, so instead of having 100 line if/else blocks, you have a single 10-line if else block, and nine 10-line subroutines, you can figure it out why it sends you back to start page instead of updating

Its very difficult to reason about a 100-line if/else block but a 10-line if/else block is easy, see Re: Adding a pop up confirmation box

#!/usr/bin/perl --
use strict; use warnings;
Main( @ARGV );
sub Main {
    my $q = CGI->new({ @_ });
    my $action = $q->param('go');
    if( !defined $action or !length $action ){
        return ShowEmployees( $q );
    } elsif( $action eq 'confirmDelete' ){
        return ConfirmDeleteEmployees( $q );
    } elsif( $action eq 'delete' ){
        return DeleteEmployees( $q );
    } else {
        return UnrecognizedAction( $q );
    }
[download]

Why doesn't employee get updated?

Does the UpdateEmployee function get called?

Does the UpdateEmployee function get all the needed arguments/parameters?

What arguments does UpdateEmployee get?

Does UpdateEmployee actually work when it gets good args?

#!/usr/bin/perl --
use strict; use warnings;
use CGI;
Main( @ARGV );
sub Main {
    my $q = CGI->new({ @_ });
    my $action = $q->param('go');
    if( !defined $action or !length $action ){
        return ShowEmployees( $q );
    } elsif( $action eq 'update' ){
        return UpdateEmployee( $q );
    } elsif( $action eq 'delete' ){
        return DeleteEmployees( $q );
    } else {
        return UnrecognizedAction( $q );
    }
}
sub UpdateEmployee {
    my( $q ) = @_;
    my $name = $q->param('name');
    my $id   = $q->param('id');
    print "name($name) id($id)\n";
}
__END__
$ perl ogg.pl
Undefined subroutine &main::ShowEmployees called at ogg.pl line 9.

$ perl ogg.pl go fish
Undefined subroutine &main::UnrecognizedAction called at ogg.pl line 1
+5.

$ perl ogg.pl go update
Use of uninitialized value $name in concatenation (.) or string at ogg
+.pl line 22.
Use of uninitialized value $id in concatenation (.) or string at ogg.p
+l line 22.
name() id()

$ perl ogg.pl go update name bob
Use of uninitialized value $id in concatenation (.) or string at ogg.p
+l line 22.
name(bob) id()

$ perl ogg.pl go update name bob id 77
name(bob) id(77)
[download]

see also another helper sub DebugCGI, see Basic debugging checklist and brian's Guide to Solving Any Perl Problem and write more subs, so you can debug small subs, not giant programs,

<input type="hidden" name="empid" value="$hr->{'empid'}"/>
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if ( ($action eq "UPDATE")  && ($custid =~ /\d+/)) {
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CustomerID 
------------
 ALFKI
 ANATR
 ANTON
 AROUT
 BERGS
 BLAUS
 BLONP
 BOLID
[download]

#!/usr/local/bin/perl
use strict;
use CGI;
use CGI::Carp 'fatalsToBrowser'; #remove for prod
use DBI;

# get form parameters
my $q = new CGI;
my $action = $q->param('go');
my $empid  = $q->param('empid');

my $dbh = dbh(); # connect to db
$dbh->do("SET search_path to northwind") or die;

# If the confirm form was properly submitted, update the record
my $msg;
# change validation to suit
if ( ($action eq "UPDATE") && ($empid =~ /\d+/)) {

  my @data=();
  my @fields = qw!lastname firstname title toc dob doh address city
                  region pcode country homephone ext notes !;
  for my $f (@fields){
    push @data,$q->param($f) || '' ;
  }  
  push @data,$empid;
                  
  my $sql = qq!UPDATE "Employees" 
               SET "LastName"  = ?,
                   "FirstName" = ?,    
                   "Title"     = ?,          
                   "TitleOfCourtesy" = ?, 
                   "BirthDate" = ?,
                   "HireDate"  = ?, 
                   "Address"   = ?, 
                   "City"      = ?,    
                   "Region"     = ?,            
                   "PostalCode" = ?,            
                   "Country"    = ?,             
                   "HomePhone"  = ?,   
                   "Extension"  = ?,            
                   "Notes"      = ?,           
             WHERE "EmployeeID" = ? !;
               
  my $count = $dbh->do( $sql,undef,@data);
  $msg = "$count Record updated - $sql, @data";
} else {
  $msg = "Please complete form";
}

# get employees
my $sql = qq!SELECT "EmployeeID" AS empid, 
             "FirstName"::text || ' ' ||"LastName"::text AS name 
             FROM "Employees" !;
my $ar = $dbh->selectall_arrayref($sql);

# Make up a pulldown menu 
my $options = qq!<option value="">select name</option>!;
for my $row (@$ar) {
  $options .= qq!<option value="$row->[0]">$row->[1]</option>\n!;
}

# build html page
my $style = q!
  body { background-color: pink ; color: #3300cc; }
  .container { width: 500px; clear: both; }
  .container input { width: 100%; clear: both;}
!;

# Send out the header and form
print $q->header;
print $q->start_html(-title=>'Update an employee record',
                     -style=>{ -code=>$style } );
print qq!<h1 style="color:3300CC">Please update an employee</h1>!;

# Fetch data
if ( $action eq "FETCH" ) {
  #print qq!<h3>Please make the necessary updates to $empid ?</h3>
  my $sql = 'SELECT * FROM "Employees" 
           WHERE "EmployeeID" = ?';
my $hr = $dbh->selectrow_hashref($sql,undef,$empid);
#my $hr = $dbh->selectrow_hashref($sql,undef,$input{empid});

print qq!
<form action="" method="post">
Employee ID : $hr->{'EmployeeID'}<br/>
<input type="hidden" name="EmployeeID" value="$hr->{'EmployeeID'}"/>
Last Name :<input name="lastname" value="$hr->{'LastName'}"/><br/>
First Name :<input name="firstname" value="$hr->{'FirstName'}"/><br/>
Title :<input name="title" value="$hr->{'Title'}"/><br/>
Title Of Courtesy :<input name="toc" value="$hr->{'TitleOfCourtesy'}"/
+><br/>
Birth Date :<input name="dob" value="$hr->{'BirthDate'}"/><br/>
Hire Date :<input name="doh" value="$hr->{'HireDate'}"/><br/>
Address :<input name="address" value="$hr->{'Address'}"/><br/>
City :<input name="city" value="$hr->{'City'}"/><br/>
Region :<input name="region" value="$hr->{'Region'}"/><br/>
PostalCode :<input name="pcode" value="$hr->{'PostalCode'}"/><br/>
Country :<input name="country" value="$hr->{'Country'}"/><br/>
Home Phone :<input name="homephone" value="$hr->{'HomePhone'}"/><br/>
Extension :<input name="ext" value="$hr->{'Extension'}"/><br/>
Notes :<input name="notes" value="$hr->{'Notes'}"/><br/>
<input type="submit" name="go" value="UPDATE"/>
</form>!;

  my $count = $dbh->do( $sql,undef,$empid );
    $msg = "$count Record fetched - $sql, $empid";

} else {
  print qq!<div class="container">
  Select Employee to be updated :
<form method="post" action="">
  <select name="empid"> $options </select><br/>
  <input type="submit" name="go" value="FETCH"/>
</form></div><hr/>!;
 
  # Standard links to the rest of the application
  print <<"FOOTER";
<b>$msg</b>
<hr/>
Jump to - <a href="emp2.pl">View Employees Listing</a><br/>
Jump to - <a href="addemp.pl">Add an Employee</a><br/>
Jump to - <a href="updatephoto.pl">Add or update Employee Photo</a><br
+/>
<hr/>
Edited by Terry on July, 06 2014.
FOOTER
}
print $q->end_html;

# connect to database
sub dbh {
  my $dsn = 'DBI:Pg:dbname=northwind;host=localhost';
  my $user = 'postgres';
  my $pwd  = 'postgres';
  my $dbh = DBI -> connect($dsn,$user,$pwd,{'RaiseError' => 1});
  return $dbh;
}
[download]

In the update form, change the name in the hidden input field to empid.

<input type="hidden" name="empid" value="$hr->{'EmployeeID'}"/>
[download]

otherwise the validation here will prevent the update

if ( ($action eq "UPDATE") && ($empid =~ /\d+/)) {
[download]

poj