note 59532 added to function.pdo-construct
| From: | Sasa dot Radovanovic at gmail dot com | Date: | Fri, 09 Dec 2005 07:08:56 +0000 |
| Subject: | note 59532 added to function.pdo-construct | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-99799@lists.php.net to get a copy of this message | ||
Since PDO can't destroyed by a call to some function e.q. close/destroy, if we'd want to
get rid of it, we'd have to destroy all references to the object.
This can be quite a hassle if our database connection is passed through a layer of objects (where
possible each object needs the db conn).
If we'd want to serialize the uppermost object, we would have to delete all references, so in
all objects, to the db conn.
(this is necessary since PDO may not be serialized)
To implement your own ISerializeable (with __wakeup and __sleep) on each object and then restoring
the db conn would be a problem,
since you'll probably only want to have the top object have knowledge about the db you're
connecting to.
(so besides destroying all handles from all objects, you'd be passing also the knowledge of
which db to access from the top object to the lower ones (on unserialization)).
To solve the upper problem you can write a wrapper around the access to the PDO object.
Here's a description of the wrapper i use for this.
The wrapper contains 4 methods, nl.:
<?php
__construct(PDO $PDO, $type, $databasename, $username, $password, $host); //store the members for
re-use in sleep and wakeup
/**
* I'm to lazy to implement all PDO methods, so I use the
* magic method __call to handle this for me
*/
final public function __call($methodName, $arrArguments) {
//also check if the method exists
return call_user_func_array(array($this->PDOHandle , $methodName), $arrArguments);
}
//destroy our handle to PDO ($this->PDOHandle = NULL;)
//and return the array containing the members we'll want to use on wakeup
public function __sleep();
//on base of our db members, let's create a new instance of the pdo object ($this->PDOHandle
= new PDO...)
public function __wakeup();
?>
This way all objects working with the database will retrieve a handle to the wrapper and only the
wrapper will contain a handle to the PDO object.
So we only have to destroy the handle on one place, to ensure we can use serialization (instead of
running through our object tree).
----
Manual Page -- http://www.php.net/manual/en/function.pdo-construct.php
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