Beefy Boxes and Bandwidth Generously Provided by pair Networks
Clear questions and runnable code
get the best and fastest answer

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

My tip which seems small but is actually big is use eval blocks for error checking.

Here is an example which happens to use DBI. DBI implements tons to error checking which uses die if you ask it to.

#up top my $dbh=DBI->connect("DBI:Pg(RaiseError=>1,AutoCommit=>0),dbname=xyzzy +"); #later eval { my($sth); $stmt="SELECT cnam_oficial FROM evocrs WHERE evocrs_id=?"; $sth=$dbh->prepare($stmt); $sth->execute($ec); $sth->bind_columns( \( $cn ) ); $sth->fetch; # $dbh->commit; #if we were writing some records instead of readin +g }; if($@) { # $dbh->rollback; #if we were doing transactions and writing data print STDERR "Could not retreive course name: $stmt: $@\n"; print "Could not retrieve course name\n"; exit; }

I delclare $stmt in a scope where the eval and the error block can both see it for reporting. The eval saves having to say or die "message" on every line of your code. The RaiseError tells DBI to die on any database error. I put the commit inside the eval as the last line because that will not be reached if there is any problem since a die will jump right out of the eval without doing the rest of the block. The rollback goes in the $@ block which is executed if the eval fails.

This makes your code nice and clean and results in errors being trapped always. The DBI module is very nice about this since RaiseError causes a die for all errors.

In reply to Re: best practice by dga
in thread best practice by George_Sherston

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, 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, 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.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others wandering the Monastery: (6)
    As of 2020-10-27 12:24 GMT
    Find Nodes?
      Voting Booth?
      My favourite web site is:

      Results (256 votes). Check out past polls.