On the PHPClasses.org blog today Manuel Lemos has posted a look at ORM - what it is and how you can use it to improve your applications.

Object-Relational Mapping, usually referred as ORM, is a software development approach to treat data stored in relational (SQL) database table records as if they were objects. Basically we can create classes with variables that represent fields of a database table. To insert a table record you need to create an object of the class, assign the variable values, and call a function of the class that takes care of inserting the table record

He illustrates what it is (brief code samples) and some of the approaches that developers have taken to implementing it. He suggests, however, that they should truely be called ROM (Relational Object Mapping) libraries rather than ORM due to the fact that they map an object (the database tables) back in to PHP objects. He finishes with a list of a few ORM resources and libraries including the one that helps power the PHPClasses website, Metastorage.

In this recent post from the Solar blog, anttih shows how to use the Solar registry to automatically load and register objects when it starts up.

Solar_Registry is a class for storing singleton objects which are used usually for things like SQL objects and the response and request objects. Now what's interesting, is that in the new version of Solar a new configuration key registry_set was added for the Solar arch-class. You can use it to tell Solar to automatically add objects to the registry when it starts up.

He compares the two methods - manual loading and the automatic version and includes a "real world" example of loading up an SMTP object.

In a new article to his blog, Ryan Campbell has expressed some concerns in the amounts of memory that some of the object oriented practices in PHP are using these days.

It's hard to imagine pushing the limits of object oriented PHP so far that your web servers choke, but the truth is those limits are reached faster than you think. [...] While replacing objects with arrays when possible makes things a little better, the most performance friendly approach involves appending strings. For your convenience, we've run some tests that measure page execution times and memory usage to create the following guideline to help you plan out what areas of your code may have to break away from an object oriented nature.

He shares some benchmarks of the memory use for different variable types - strings, arrays and objects - giving load times and the amounts of memory used. He mentions three workarounds that could help (unset, static methods and paging) reduce the memory consumption of your script.

On the PHP in Action blog, there's a new post looking at a recent library that was posted to support type hinting on scalars. They agree with his choice of subjects, noting that they see type hinting as much more useful on scalars than on objects.

I admit that these judgments are hard to make. I could be wrong, more or less. Type hints are probably useful when code becomes stable enough and at the boundaries between modules. But I still tend to avoid using them until I get an actual bug that might have been prevented by a type hint. Their usefulness is and has to be an empirical question. The purpose of using them has to be catching errors earlier, so if they don't have that effect, there's no point.

He lists three reasons why he had given up on type hinting before, one being the limited usefulness when it came to objects. Applying it to scalars is a different matter, though, and can prevent improper passing of array/scalars when the other is needed.

Lorna Mitchell has posted the last part of her development process towards creating a sample REST server in PHP:

This is part 3 of my article about writing a restful service server. If you haven't already, you might like to read part 1 (covering the core library and grabbing the information we need from the incoming request) and part 2 (covering the service handler itself) before reading this section. This part covers the Response object that I used to return the data to the user in the correct format.

She show how she created the object to push the response back out to the client with an output() method that displays the XML response in a manually generated format.

David Otton has a handy little tip if you're looking for a cleaner way to deal with array data - casting it to an object.

Array notation is fine, but it can look a bit clunky when you're working with complex structures. [...] Casting the array to an object allows us to use object notation (->) and makes the code more readable.

He includes examples of the casting, showing the difference between the array and object notations including a method for creating an object based on a simple array that has basic properties built in. This sort of transformation can be useful if you want consistency through out the application - just passing objects with their properties rather than arrays.

Havard Eide has a recent post to his blog that looks at a part of the Standard PHP Library (SPL) that can be used with objects to store them for later use - SplObjectStorage.

In this post I will look at SplObjectStorage: a container that allows to store objects uniquely without the need to compare them one by one.

He lets the code to most of the talking, showing how to do the standard operations for a data store - adding objects (both unique and the same), updating objects in the store, checking to see if an object is already added and removing an object from storage.

Eran Galperin has a few misconceptions in web development posted to his blog today (for both front and back-end development).

Here's his list:

• OO code is less performant than procedural code
• The backend is the most important part of development
• Graphical designers are good at user interface design
• The existence of a superior programming language
• XML is more economic than a DB

While the others touch on some topics that could be PHP related, he focuses on it in #1. He points out that sometimes making classes and objects and interfaces and...well, you get the idea...is just too much and that procedural code can be the quick hit you need.

On the PHP::Impact blog Federico Cargnelutti has posted a comparison of using static factory methods to create an instance of a class versus making an object, calling the constructor.

Normally, creating an instance of a class is done by calling new, which calls the constructor. Static factory provides a static method that returns an instance of the class. So, you are using static factory instead of the constructor. Providing a static factory method instead of a public constructor has both advantages and disadvantages.

He includes some of the advantages of the factory method and others for the normal call to create an object. He also mentions some comments made by Dagfinn Reiersol in a blog post about public constructors.

A recent post on the Developer Tutorials blog takes a look at a fundamental part of several of the PHP (and other language) frameworks out there - the Object Relational Mapping (ORM) layer for database access.

Instead of direct database access, an ORM layer in a PHP framework can make "objects" stored in a database behave like actual objects from a programming perspective - for example, creating a new "car" stored in the database could involve a call to $car->new(). By abstracting actual database access, web development can be more productive and result in more reliable applications. Here's a quick intro to ORM in PHP.

They talk about ORM's role in how applications interface with data (abstracted out to objects) and some examples of it in current frameworks - CakePHP and Symfony.