The function DB::isError will check to see whether the result that's been returned to you is an error or not. If it is an error, you can use DB::errorMessage to return a text description of the error that was generated. You need to pass DB::errorMessage the return value from your function as an argument.

Here you rewrite the PEAR code to use error checking:

  <?php
  if ( DB::isError( $demoResult = $db->query( $sql)))
  {
     echo DB::errorMessage($demoResult);
  } else {
     while ($demoRow = $demoResult->fetchRow()) {
            echo $demoRow[2] . '<br />';
     }
  }
  ?>

Now that you have a good handle on connecting to the database and the various functions of PEAR, we're going to talk about forms. Forms provide a way to send substantial data from the user to the server where it can be processed.

Question 9-1.  Create a PEAR-style connect string to connect to this database:

hostname: oreilly.com

database name: survey

username: joe

password: my$ql

Question 9-2.  Using the parameters in Question 9-1, write the non-PEAR PHP code to connect to a database and select the instance.

Question 9-3.  Using the connection from Question 9-2, write the non-PEAR PHP code to fetch and display the results of the query select * from authors;.

Question 9-4.  What are the advantages of using PEAR?

See the Appendix for the answers to these questions.