I usually do something like this (pseudo-code != Perl): 

if (data_submitted()) {
    @errors = validate_data();
    if (@errors) {
        output_errors(@errors);
        output_form();
    }
    else {
        process_data();
    }
}
else {
    output_form();
}

[download]

Forms appearence, data validation and processing are VERY application specific, so I don't think that you might cheat a lot there. On the other hand, the validate_data() sub can win a lot from simplified validations. I'd say that it would be very helpful if I could do something like this (pseudo-code again): 

push @errors, "Age not in range" if (!is_integer($age,5,100));
push @errors, "Ugly date format" if (!is_date($date,"YYYY-MM-DD"));
push @errors, "Unknown image type" if (!is_file_type($uploaded_file, "
+image/jpeg"));

[download]

Leonid Mamtchenkov

In reply to Re: Data format verification for insertion into a database by TVSET
in thread Data format verification for insertion into a database by antirice

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.