http://phpdatamapper.com

You may find you like it, and it may be valuable to your visitors!

I have one question: If I was to include summary data, not necessarily objects but simple scalar values, like a post count in your application, where would the data access code for that reside? It doesn’t seem to fit in the data mapper class itself, yet the data objects are meant to be database agnostic.

The best I can think at this time is a Posts and PostsMapper pair where Posts has some methods to get summary information like post counts for users etc but this seems messy.

Hope this is clear enough. Many thanks,
Maz

If you widen your search a bit you will come a cross a book called Patterns of Enterprise Application Architecture written by Martin Fowler, now this is a good book. All examples are in Java or C# however.

I know I asked before, but could you please suggest some good php books, have been developing in php4 for ages and it’s finally time to take a step to a more object oriented programming (MVC-framework, patterns, etc). Could you please suggest some or point in the right direction? Thanks!

A fellow Swede.

See you on part 3, Kyle

Thanks for your comment :), here’s my thoughts on your two points:

1) This is a matter of ideology I think, if you should be able to effect a row in the database without loading it first. I don’t think you should, and such an update “action” would require you to first load the object and then save it with the modified field. Well, it’s also a matter of performance.

2) Well, the $map attribute is defined in DataMapper which is the parent class to both UserMapper and PostMapper and thus they can access it (as far as I know this is all according to what people refer to as a proper object model) however if I would’ve defined an attribute just in UserMapper and protected it then no, PostMapper would not be able to access it.

once again: Two thumbs up! I’m eager to see your doctoral thesis ;)

Two small things:

1.) Once again your code should not depend on the way it is used. Your implementation of save() assumes, that existing objects are loaded (and stored in the IdentityMap) before they are saved/updated. If you have an update page for user object and a user changed his name you get a new user if you don’t load it first.

Bad code:
…
$user = new User( $_POST[’ID’], $_POST[’NAME’] );
$userMapper->save( $user ); // new user created!
…

So DataMapper::save() might better use “if( $obj->getId() !== null && $this->find( $obj->getId ) )” to check if an object is existing.

2.) I’m not sure if it works in PHP, it shouldn’t anyway: Accessing the UserMappers “map” in PostMapper should not work, since it is a protected variable in a different class’s instance.

Regards, Kyle