You didn't ask about the password part specifically, although your subject hints at it. If you want to verify the password, the previous resp are right on - you just might want to use Digest::MD5 to build a one-way hash to store your password strings rather than plain-text strings. A lost password would need to get reset rather than recovered but this gives you a more reasonable level of security for a little bit of code. Have to use the same md5 function when building the user/password table. 
use Digest::MD5 qw(md5);
# ... assume that $dbh was initialize previously ...
my $query = qq(SELECT count(*) FROM user WHERE username=? AND password
+=?);
my $sth = $dbh->prepare($query);

$sth->execute($user,md5($password));
($rc) = $sth->fetchrow_array;
if( $rc == 1 ) {
 # user and pass matched
} else { 
 # user and pass did not match (rc == 0 ) or 
 # you don't have a unique key for user/pass (rc > 1)
}

[download]

In reply to Re: username and password verification from a table in Postgres by stajich
in thread username and password verification from a table in Postgres by Anonymous Monk

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.