PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

Implementing User Authentication
583
Listing 27.9
}
Continued
if ($result->num_rows>0) {
throw new Exception('That username is taken - go back and choose another
one.');
}
// if ok, put in db
$result = $conn->query("insert into user values
('".$username."', sha1('".$password."'), '".$email."')");
if (!$result) {
throw new Exception('Could not register you in database - please try again
later.');
}
}
return true;
There is nothing particularly new in this function; it connects to the database you set up
earlier. If the username selected is taken or the database cannot be updated, it will throw
an exception. Otherwise, it will update the database and return true.
Note that you are performing the actual database connection with a function called
db_connect(), which we wrote.This function simply provides a single location that contains
the username and password to connect to the database.That way, if you change the
database password, you need to change only one file in the application.The db_connect()
function is shown in Listing 27.10.
Listing 27.10 db_connect()Function from db_fns.php—This Function Connects to
the MySQL Database
When users are registered, they can log in and out using the regular login and logout
pages.You build them next.