I wanted to extend PDO class to store statistics of DB usage, and I faced some problems. I wanted to count number of created statements and number of their executings. So PDOStatement should have link to PDO that created it and stores the statistical info. The problem was that I didn't knew how PDO creates PDOStatement (constructor parameters and so on), so I have created these two classes:
<?php
class PDOp {
protected $PDO;
public $numExecutes;
public $numStatements;
public function __construct($dsn, $user=NULL, $pass=NULL, $driver_options=NULL) {
$this->PDO = new PDO($dsn, $user, $pass, $driver_options);
$this->numExecutes = 0;
$this->numStatements = 0;
}
public function __call($func, $args) {
return call_user_func_array(array(&$this->PDO, $func), $args);
}
public function prepare() {
$this->numStatements++;
$args = func_get_args();
$PDOS = call_user_func_array(array(&$this->PDO, 'prepare'), $args);
return new PDOpStatement($this, $PDOS);
}
public function query() {
$this->numExecutes++;
$this->numStatements++;
$args = func_get_args();
$PDOS = call_user_func_array(array(&$this->PDO, 'query'), $args);
return new PDOpStatement($this, $PDOS);
}
public function exec() {
$this->numExecutes++;
$args = func_get_args();
return call_user_func_array(array(&$this->PDO, 'exec'), $args);
}
}
class PDOpStatement implements IteratorAggregate {
protected $PDOS;
protected $PDOp;
public function __construct($PDOp, $PDOS) {
$this->PDOp = $PDOp;
$this->PDOS = $PDOS;
}
public function __call($func, $args) {
return call_user_func_array(array(&$this->PDOS, $func), $args);
}
public function bindColumn($column, &$param, $type=NULL) {
if ($type === NULL)
$this->PDOS->bindColumn($column, $param);
else
$this->PDOS->bindColumn($column, $param, $type);
}
public function bindParam($column, &$param, $type=NULL) {
if ($type === NULL)
$this->PDOS->bindParam($column, $param);
else
$this->PDOS->bindParam($column, $param, $type);
}
public function execute() {
$this->PDOp->numExecutes++;
$args = func_get_args();
return call_user_func_array(array(&$this->PDOS, 'execute'), $args);
}
public function __get($property) {
return $this->PDOS->$property;
}
public function getIterator() {
return $this->PDOS;
}
}
?>
Classes have properties with original PDO and PDOStatement objects, which are providing the functionality to PDOp and PDOpStatement.
From outside, PDOp and PDOpStatement look like PDO and PDOStatement, but also are providing wanted info.