simple example of how to use a db access class

[Anonymous via the Cypherpunks Tonga Remailer]

Hi,

I'm building a simple Object Oriented CMS using PHP5
and the new object model (new to both). I'm looking
for some design advice on how best to integrate the
database class - which creates the db connection and
executes the sql queries. In my particular case,
I have 3 objects (classes) that I instantiate from
a given script (call it index.php). Each must have
access to the database. So, do I create a db connection
once and declare it 'global' in the various classes?
or do I create a db connection in each class - maybe
in the constructor? or is there some other practice
that's widely accepted? Any recommendations are
greatly appreciated.

<?php
// index.php
$dbconn = csite::DB();

$a = new cvisitor();
$b = new cvalid8r();
$c = new cnode();

... blah blah
?>

<?php
// cvisitor.php
class cvisitor {
public function __construct() {
}
public function __destruct() {
}

public function getVisitor() {
// open the db
global $dbconn;

... do the db stuff
?>

Thanks,
b

[Chung Leong]

Anonymous via the Cypherpunks Tonga Remailer wrote:

Hi,

I'm building a simple Object Oriented CMS using PHP5
and the new object model (new to both). I'm looking
for some design advice on how best to integrate the
database class - which creates the db connection and
executes the sql queries. In my particular case,
I have 3 objects (classes) that I instantiate from
a given script (call it index.php). Each must have
access to the database. So, do I create a db connection
once and declare it 'global' in the various classes?
or do I create a db connection in each class - maybe
in the constructor? or is there some other practice
that's widely accepted? Any recommendations are
greatly appreciated.
Don't use global variables if you can help it. They create runtime
dependencies in your code, making your code less reuseable and harder
to understand/debug.

A general technique I use for such situations is to call a function to
retrieve the database connection. The function itself would use a
static variable to cache the handler, so that it wouldn't need to go
through the same motion when it's called again:

function GetDatabaseConnection() {
static $connection;
if(is_null($connection)) {

/* open the connection */
$connection = ???

}
return $connection;
}

Another way to model it is to pass the database connection in each
call:

getVisitor($dbconn);

That gives your more flexibility, since your code could potentially
operate on different databases.

<?php
// index.php
$dbconn = csite::DB();

$a = new cvisitor();
$b = new cvalid8r();
$c = new cnode();

... blah blah
?>

<?php
// cvisitor.php
class cvisitor {
public function __construct() {
}
public function __destruct() {
}

public function getVisitor() {
// open the db
global $dbconn;

... do the db stuff
?>

Thanks,
b