Setting PHP Class variable with a variable call - php

Question

I am modifying a script that I bought and I am having trouble making the Database name variable that is set in the Database class be the result of the variable I construct above it. I need the $dbName variable to be set to the combination of "mmo_" appended to the variable $username that I get from my database. The name of the database should be "mmo_school" with school being the $username variable that is pulled from database. However, it fails unless I put the text of the variable in single quotes after $dbName = . But I need the database name to be dynamically set based on which user is using the script. I hope that this makes sense and I really appreciate your help!!
$username = "school";
$newname = "mmo_" . $username; **// the results of this would be "mmo_school"**
class Database
{
private static $dbName = $newname ;
private static $dbHost = 'localhost' ;
private static $dbUsername = 'username';
private static $dbUserPassword = 'password';
private static $cont = null;
public function __construct() {
exit('Init function is not allowed');
}
public static function connect() {
// One connection through whole application
if ( null == self::$cont ) {
try {
self::$cont = new PDO( "mysql:host=".self::$dbHost.";"."dbname=".self::$dbName, self::$dbUsername, self::$dbUserPassword);
} catch(PDOException $e) {
die($e->getMessage());
}
}
return self::$cont;
}
public static function disconnect() {
self::$cont = null;
}
}
if I type in $dbName = 'mmo_school' ; THIS WORKS.
if I try to use the variable I create as shown above...IT DOESN'T!!!
THANKS FOR YOUR HELP!!

Answer 1

Create a public static method to set the host, username, password, and etc. Also, i would change your constructor to private not public.
Database::setDB('mmo_' . $username);
// or
Database::setConnectInfo('mmo_' . $username, 'some host', $username, 'some password');
$db = Database::connect();
class Database
{
private static $dbName = $newname ;
private static $dbHost = 'localhost' ;
private static $dbUsername = 'username';
private static $dbUserPassword = 'password';
private static $cont = null;
private function __construct() {
exit('Init function is not allowed');
}
public static function setDB($dbName){
self::$dbName = $dbName;
}
// or use this function
public static function setConnectInfo($dbName, $dbHost, $dbUsername, $dbUserPassword){
self::$dbName = $dbName;
self::$dbHost = $dbHost;
self::$dbUsername = $dbUsername;
self::$dbUserPassword = $dbUserPassword;
}
public static function connect() {
// One connection through whole application
if ( null == self::$cont ) {
try {
self::$cont = new PDO( "mysql:host=".self::$dbHost.";"."dbname=".self::$dbName, self::$dbUsername, self::$dbUserPassword);
} catch(PDOException $e) {
die($e->getMessage());
}
}
return self::$cont;
}
public static function disconnect() {
self::$cont = null;
}
}

Answer 2

In your class you have to call $newname as a global variable. With this minor change your code should work.
$username = "school";
$newname = "mmo_" . $username; **// the results of this would be "mmo_school"**
class Database {
private static $dbName = "" ;
private static $dbHost = 'localhost' ;
private static $dbUsername = 'username';
private static $dbUserPassword = 'password';
private static $cont = null;
function __construct($init_parameter) {
global $newname;
$this->$dbName = $newname;
}
public static function connect() {
// One connection through whole application
if ( null == self::$cont ) {
try {
self::$cont = new PDO( "mysql:host=".self::$dbHost.";"."dbname=".self::$dbName, self::$dbUsername, self::$dbUserPassword);
} catch(PDOException $e) {
die($e->getMessage());
}
}
return self::$cont;
}
public static function disconnect() {
self::$cont = null;
}
}

Answer 3

because single quotes don't do variable expansion - use double quotes
$var = 'dingo';
$name = 'xyz_$var'; // result 'xyz_$var'
$name = "xyz_$var"; // result 'xyz_dingo'