You always should check for errors, maybe the insertion just doesn't happen for some reason and that's why there is no last_insert_id.

Depending on how you open/manage your DB connection, you might want either to raise an exception on error that you would trap within an eval {}; block, or explicitely check the result/error code.

Have a look into DBD::mysql, maybe it helps a bit.

Depending on the chosen way to deal with errors, your code probably should look like
my $tmp_query="insert into <TableName> values('','');"; 
eval {
  $sth = $dbh->prepare($tmp_query); 
  $sth->execute();
  $sth->finish();
};
if ($@) { # error...
}

[download]
or 
  $sth = $dbh->prepare($tmp_query); 
  if (!$sth) {
     die "Error:" . $dbh->errstr . "\n";
  }
  if (!$sth->execute) {
     die "Error:" . $sth->errstr . "\n";
  }
  ...

[download]

In reply to Re: Getting null value from last_insert_id() by Krambambuli
in thread Getting null value from last_insert_id() by chiragforever

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.