Re: green bean question on singleton php5

julian schreef:

you are forcing the no instantiation via abstract, instead of hiding via private method constructor.

you want to garantee a single instance of the mysqli object - who cares exactly how this is done. besides which the whole exercise is bogus. you want a DB connection abstraction that allows to create connections to multiple DBs and given a given set of connection parameters to always return the same connection object ... which is not exactly the same as a singleton (at all) given that dbaccess doesn't extend mysqli instantiation of dbaccess is completely pointless no?

You change the constructor for an init function. still the $dummy = new dbaccess ()..... looks like a simpler solution....

no idea what you mean, personally I can't see anything complicated in any of these examples - I couldn't find a post showing something with $dummy.

Thanks for your comments Jochem Maas wrote:

julian schreef:

Hi, I am implementing this

try comparing this rewrite with your version: abstract class dbaccess { static $db = null; private static function init() {

    if (dbaccess::$db))
    return;

    dbaccess::$db = new mysqli("localhost",USER,PASSWD,DB);
    if(mysqli_connect_errno())        throw new Exception('cannot connect to DB');

} public static function getDB() {

    self::init();
    return dbaccess::$db;

} } try {

    $db = dbaccess::getDB();
    $db->query("SELECT foo FROM bar WHERE qux=1");

} catch (Exception) {

    die($e->getMessage());

}

class dbaccess{ static $db=null; static $othervar=33;

      private  function dbaccess(){
    dbaccess::$db= new mysqli("localhost",USER,PASSWD,DB);
    if(mysqli_connect_errno()){
      echo "no way";
    }

}

    public static function GetDb(){

if(dbaccess::$db==null){

dbaccess is a static class, you should not be constructing it here it!

dbaccess::$db= new dbaccess(); } return dbaccess::$db;

      }

} $db=dbaccess::GetDE(); $db->query(..................); will fail...with Call to undefined method dbaccess::query() apparently $db is of type dbaccess... and thus has not does not have query implemented.... any hhelp appreciated..... JCG