ZEND PHP 5 Certification STUDY GUIDE

Differences Between PHP 4 and 5 ” 255
• __isset() is called when passing an undefined property to the isset() construct.
• __unset() is called when passing an undefined property to unset().
• __toString() is called when trying to directly echo or print() an object.
• __set_state() is inserted dynamically by var_export() to allow for reinitialization
on execution of var_export()’s output.
Selected New Extensions
• SimpleXML allows easy access to XML data using object and array notation.
• PHP 5 also introduces a DOMXML, DOMXSL and Sablotron replacement in
the form of the libxml2-based DOM and XSL extensions.
• The PHP Data Objects (PDO) extension provides a unified database access extension
that allows access to many different types of database systems by using
a common interface. PDO is not an abstraction layer—except for prepared
queries, it does nothing to abstract the actual database code (SQL), itself.
• The hash extension is a new replacement for the GPLed libmhash; it was added
to the PHP core starting with version 5.1.2. It can produce hashes using many
algorithms, including the familiar MD5 and SHA1, as well as some more secure
(albeit slower) algorithms, such as snefru.
• The Standard PHP Library (SPL) provides numerous interfaces that enhance
the way classes interact with the PHP language, including the new Iterator
interfaces.
Licensed to 482634 - Amber Barrow (itsadmin@deakin.edu.au)
• The new Reflection extension allows for runtime introspection of executing
PHP code.