C.11 Chapter 12

C.11.1 Exercise 1:

The error message looks like:

Parse error: parse error, unexpected T_GLOBAL in exercise-12-1.php on line 6

The global declaration has to be on a line by itself, not inside the print statement. To fix the program, separate the two:

<?php
$name = 'Umberto';
function say_hello( ) {
    global $name;
    print 'Hello, ';
    print $name;
}
say_hello( );
?>

C.11.2 Exercise 2:

function validate_form( ) {
    $errors = array( );
    // Capture the output of var_dump( ) with output buffering
    ob_start( );
    var_dump($_POST);
    $vars = ob_get_contents( );
    ob_end_clean( );
    // Send the output to the error log
    error_log($vars);
    // operand 1 must be numeric
    if (! strlen($_POST['operand_1'])) {
        $errors[  ] = 'Enter a number for the first operand.';
    } elseif (! floatval($_POST['operand_1']) =  = $_POST['operand_1']) {
        $errors[  ] = "The first operand must be numeric.";
    }
    // operand 2 must be numeric
    if (! strlen($_POST['operand_2'])) {
        $errors[  ] = 'Enter a number for the second operand.';
    } elseif (! floatval($_POST['operand_2']) =  = $_POST['operand_2']) {
        $errors[  ] = "The second operand must be numeric.";
    }
    // the operator must be valid
    if (! in_array($_POST['operator'], $GLOBALS['ops'])) {
        $errors[  ] = "Please select a valid operator.";
    }
    return $errors;
}

C.11.3 Exercise 3:

Change the beginning of the program to:

<?php
require 'DB.php';
require 'formhelpers.php';
// Connect to the database
$db = DB::connect('mysql://hunter:w)mp3s@db.example.com/restaurant');
if (DB::isError($db)) { die ("Can't connect: " . $db->getMessage( )); }
function db_error_handler($error) {
    error_log('DATABASE ERROR: ' . $error->getDebugInfo( ));
    die('There is a ' . $error->getMessage( ));
}
// Set up automatic error handling
$db->setErrorHandling(PEAR_ERROR_CALLBACK,'db_error_handler');

C.11.4 Exercise 4:

Here are the errors in the program:

• Line 5: Two colons are needed between DB and connect.

• Lines 9 and 10: The fetch mode should be set to DB_FETCHMODE_ASSOC since rows are treated as arrays in the rest of the program. (Alternatively, you could change lines 15 and 25-28 so that they treat rows as objects.)

• Line 15: There is an extra closing square bracket after $row['dish_id'].

• Line 17: This should be a call to $db->query( ), not $db->getAll( ), because fetchRow( ) is used in line 23 to retrieve each row. The SQL query is also wrong: it should be SELECT * FROM customers ORDER BY customer_name (only one asterisk after SELECT and customer_name, not phone DESC, after ORDER BY).

• Line 18: The method name that returns the number of rows retrieved by query( ) is numRows( ), not num_rows( ).

• Line 22: The string has mismatched delimiters. Either change the opening quote to a double quote or the closing quote to a single quote.

• Line 26: The array key is misspelled. It should be customer_name, not cutsomer_name.

• Line 28: $customer['favorite_dish_id'] is the integer ID of the favorite dish. To display the dish name, you need to look up the appropriate element in $dish_names. Instead of $customer['favorite_dish_id'], it should be $dish_names[ $customer['favorite_dish_id'] ].

• Line 31: The curly brace to end the else code block is missing.

Here is the complete corrected program:

<?php
require 'DB.php';
require 'formhelpers.php';
// Connect to the database
$db = DB::connect('mysql://hunter:w)mp3s@db.example.com/restaurant');
if (DB::isError($db)) { die ("Can't connect: " . $db->getMessage( )); }
// Set up automatic error handling
$db->setErrorHandling(PEAR_ERROR_DIE);
// Set up fetch mode: rows as associative arrays
$db->setFetchMode(DB_FETCHMODE_ASSOC);
// get the array of dish names from the database
$dish_names = array( );
$res = $db->query('SELECT dish_id,dish_name FROM dishes');
while ($row = $res->fetchRow( )) {
    $dish_names[ $row['dish_id'] ] = $row['dish_name'];
}
$customers = $db->query('SELECT * FROM customers ORDER BY customer_name');
if ($customers->numRows( ) =  = 0) {
    print "No customers.";
} else {
    print '<table>';
    print '<tr><th>ID</th><th>Name</th><th>Phone</th><th>Favorite Dish</th></tr>';
    while ($customer = $customers->fetchRow( )) {
        printf('<tr><td>%d</td><td>%s</td><td>%s</td><td>%s</td></tr>',
               $customer['customer_id'],
               htmlentities($customer['customer_name']),
               $customer['phone'],
               $dish_names [ $customer['favorite_dish_id'] ]);
    }
    print '</table>';
}
?>