Hi all

I'm attempting to train myself to code in an OOP way with PHP5. Been working through the PHP.net tutorial and also O'Reilly's Upgrading to PHP5.

Problem: my extension of an abstract class produces a fatal error and I cannot see why. There may be other stupid errors in the code, but I want to know the reason for the fatal error. Here's the abstract class:

abstract class AbsDatabase { //Abstract class defining the methods required in a DB class
	abstract public function connecting();
	abstract public function query();
	abstract public function fetch();
	abstract public function closing();
}

And here's the extension:

// Enable PHP5 to load class file on the fly
function __autoload($class_name) {
	require_once("classlib/$class_name.php");
}

class MySQLi_norman extends AbsDatabase {
	protected $dbh;
	protected $query;
	public $result;

public function connecting($server, $user, $password, $db)
{
	$this->dbh = mysqli_connect($server, $user, $password, $db);
}

public function query($sql)
{
	$this->query = mysqli_query($this->dbh, $sql);
}

public function fetch()
{
	$this->result = mysqli_fetch_array($this->query, MYSQLI_NUM);
	return $this->result;
}

public function closing()
{
	mysqli_close($this->dbh);
}
}

// Now test it ...
$db_test = new MySQLi_norman;

$db_test->connecting("localhost", "root", "password", "test");
$db_test->query("SELECT name FROM php_test");
$string = $db_test->fetch();

echo "<html><head><title>Mysqli test</title></head><body>My dad's name is: ";

printf("%s", $string[0]);

echo "<br /></body></html>";
// And so on ...

And here's the fatal error:

Fatal error:
Declaration of MySQLi_norman::connecting()
must be compatible with that of
AbsDatabase::connecting() in
/usr/local/apache2/htdocs/general_test/abstract_class_use.php on line 15

Any pointers much appreciated.

Norm

    Your concrete methods have parameters whereas the abstract methods don't. The signatures must be the same.

      Thanks Shrike

      This has been one of the many, many errors I've run across in the O'Reilly book. I really am less than impressed by the amazingly sloppy code examples. Fortunately, I've spotted most of them myself. It's disappointing, because O'Reilly is usually very precise and reliable. However, I shall look on it as an intelligence test.

      Marking resolved.

      Norm

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