Comments on: PHP 5 Design Pattern : Singleton

By: Adam

Adam — Wed, 09 Jan 2008 14:23:18 +0000

Don’t you just love singletons!

By: Tom Barta

Tom Barta — Thu, 29 Nov 2007 04:43:31 +0000

I agree with other methods than an explicit singleton is overkill – design patterns used for the sake of themselves are worthless. The important question is “what problem am I trying to solve?” If all you want is a single entrypoint to access the database, this would be more straightforward (sorry if formating doesn’t work well):

class MysqlDB {

// complete class definition to connect to a mysql db

}

function getSiteDB() {

static $db = new MysqlDB(USER, PASS, HOST, …);

return $db;

}

getSiteDB()->query(…);

Why is this better? Because this increases the usability of the database object. If a single script needs to connect to 5 different databases, it’s now possible without having to mess with singletons. Plus, now the database class definition is reusable across different projects (anytime you need a MySQL database connection), because the specifics of the particular site are layered on top of the MysqlDB object, instead of embedded into it.

By: sach

sach — Tue, 27 Nov 2007 16:47:32 +0000

et pourquoi pas faire juste une fonction globale ?

(je sors)

By: bungle

bungle — Fri, 23 Nov 2007 17:33:25 +0000

“Also note, that there’s a significant difference between singletons in PHP and other languages.”

And that’s what makes them unneeded for PHP. PHP scripts should be straightforward and to the point (and they share nothing). These singleton abstraction layers only complicate PHP processing for no added benefits.

By: PHP 5: MySQL Singleton Example | eKini Web Development Blog

PHP 5: MySQL Singleton Example | eKini Web Development Blog — Fri, 23 Nov 2007 03:32:38 +0000

[...] Here is a good example of using a Singleton. [...]

By: Ivo Jansch

Ivo Jansch — Thu, 22 Nov 2007 21:11:23 +0000

Also note, that there’s a significant difference between singletons in PHP and other languages. In most languages, Singletons follow your definition ‘one instance across the system’. In PHP, the singleton that you are creating is ‘one instance per request’. Usually this is ok, but if you’re coming from other languages and used to using Singletons in their pure form, it might be confusing.

By: JavaGalaxy.com

JavaGalaxy.com — Thu, 22 Nov 2007 17:10:30 +0000

A little more explanation on using this patten in a real time application would be helpful.

By: FlorentG

FlorentG — Thu, 22 Nov 2007 15:55:13 +0000

Remember to read “Singletons Are Evil” ( http://c2.com/cgi/wiki?SingletonsAreEvil ). Lots of people uses Singleton only to replace globals variables, because it makes them feel they’re not using globals anymore.

By: Antoine Ughetto

Antoine Ughetto — Thu, 22 Nov 2007 15:44:01 +0000

We have just make some upgrades with syntax highlighting. Hope it will be easy to read

By: butters

butters — Thu, 22 Nov 2007 15:34:09 +0000

Nice post, but i find its hard to read. Not because of the content, but the design makes it extremly difficult…

By: PHPDeveloper.org

PHPDeveloper.org — Thu, 22 Nov 2007 13:10:37 +0000

Make Me Pulse Blog: PHP 5 Design Pattern : Singleton…

On the Make Me Pulse blog today, Antoine Ughetto takes a ……

By: Dougal

Dougal — Thu, 22 Nov 2007 12:27:04 +0000

Duude… get some syntax highlighting

I like to write it like this, so its easier to copy accross classes etc.

public static function getInstance(){

if (self::$instance === null) {

$x = __CLASS__;
self::$instance = new $x;

}

return self::$instance;

}