CGI style -- alternatives to HIDDEN parms?

[Tim Chambers]

Dear Perl Mongers,

I am writing a Perl CGI script that updates some information in a database.
The field can be hundreds of lines of text. If the field hasn't been
touched, then I don't want to update it in the database. (The database logs
updates, and we don't want redudant log entries.) The user will press a
Submit button, at which point I need to decide which fields to update in the
database. I'm assuming there isn't a simple way of detecting which fields
were modified from their initial values. Am I wrong? I see my options this
way:

1. Query the database and compare before deciding whether to update. The
downside is that database queries are relatively expensive in time and
resources.

2. Use a HIDDEN parm to forward the original field contents, then compare it
with the new value to see if it's changed. But I'm concerned about sending
contents (remember -- the field could be hundreds of lines of text) back and
forth between client to server. Should I be? I studied
http://www.w3.org/TR/html4/interact/forms.html but found nothing talking
about length limits on such data.

3. Cache it on the server somehow. This would just be a cache of the
database, though.

I'm leaning toward #2. It seems wasteful, though.

What do you all think?

<>< Tim