A couple of PMish things first.

• The formating of your node is not conducive to anyone wanting to read it. Try little things, like paragraphs!
• Make it clear what your question *really* is, what your goal is, etc.
• Show us your code so far, and inbetween <code> tags

Okay, having said that, HTML::Template is your new best friend. For starters, it will allow you to create HTML pages with placeholders for your data, separating the HTML from your Perl. It's nice to compartmentalize the two types of code. There is a nice HTML::Template community and a search of the Monastery, or even Google will turn up all sorts of help. E.g., jeffa's great tutorial.

When you have some code written, come on back here and give us a looksie, and maybe we can offer more effective help.

A beginning programmer might think to write separate cgi scripts for each task (display, insert and delete) but I'd prefer a single script to keep it all together to make changes more simple. Call the script with a "mode" argument to trigger the right functions to display the forms and have them react appropriately. Make certain to consider security since this is usually necessary even for an intranet environment.

Since you already have the Perl-MySQL part done, the documentation for the standard CGI module can probably give you the rest. This includes a few examples to build from.

If want a recommendation for a book, you might look into the PerlMonks' Reviews, e.g., MySQL and Perl for the Web.

Then first thing you need to do it get yourself a whiteboard. A really big one. Put it on your wall, besides your desk.
If anybody looks at you funny, ignore them.

Make yourself a list of the various different things that your interface can do.

I am going to assume here that this is for intercompany use in a closed network, that is some kind of list management trinket for your organization, that there is no login, etc.
It's just a web front end (a gui (graphical user interface)) to something.

For example.

1)database management
 create database
 drop database (?)
 check database being present

2)querying
 list present records
 insert new record
 replace record
 delete record

3)graphical front end
 display present records as html
 display option to insert new record (form html)
 give feedback about new record (success or fail)

Now, let's give namespaces to these things, what should the subs be named?
(Remember, you are still usinng the whiteboard. Your computer is off.)

# this is PSEUDOCODE

# DATABASE SETUP & MANAGEMENT
sub database_create {}
sub database_check_exists {}
sub database_create_tables {}
sub database_drop {}

# DATABSE QUERYING / INTERACTION
# there is NO html here, this is just code

sub record_new {}

sub record_delete {}

sub records {} # returns ids for all records present

sub record_get{}

sub record_replace {
  #this may or may not be how you want to 'replace'
  record_delete($id)
  record_insert($id,{ 
    vlanid => $vlanid, 
    ipaddr => $ipaddr,
    descr => $descr
  });
}

# GRAPHICAL INTERFACE

sub show_records {
  my @records = records()  ;
  for(@records){
   record_get()
   etc etc
}
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What I'm trying to get at is that you should plan out everything. And that you should separate everything. This is not php, the human interface element is the last thing to address.

You want to separate what your code does with the idea of interaction, the html. This is very important. Your application should be able to get tested, without using a web browser.

Consider developing a test suite, tests.

If you are looking to maybe coding perl for your career, you will learn to use tests.

Later on.. after you know this material.. you will likely be using CGI::Application for something like this.

I got my start learning perl and perl/mysql programming from the book "CGI Programming 101." The book is available, including the first several chapters for free online, here:

http://www.cgi101.com/book/

Here's an article with some helpful tips on putting IP addresses into mysql.