[TYPO3-mvc] Getting started with ExtBase

[Jochen Rau]

On 2009-05-27 10:53:48 +0200, Sebastian Gebhard 
<s.gebhard at markenmotiv.de> said:

> Sebastian KurfŸürst schrieb:
>> - First, create some pseudo-UML diagrams on a Blackboard or a sheet of paper
> 
> I'm at this step now. And I struggle to decide which entities of my 
> extension are model objects and which are value objects.

Well let's reformat this sentence: "I'm at this step now. And I 
struggled to decide which objects of my extension are entities and 
which are value objects."

> I took a look at blog_example and I do not understand why the tags are 
> model objects. They have no identity, once the name changes they are 
> something different, right?

Tags are value objects because they don't have a intrinsic (or let's 
say "hidden") identity. The identity of a tag is only defined by its 
value (the name of the tag). If the name changes, the tag has a 
different identity. This has consequences on how the frame-work handles 
those objects.

A person object is an entity because it has an intrinsic identity: Even 
if all the properties of the object will change (I know Robert and 
Karsten will disagree with me in this point ;-) ).

To decide whether an object is an entity or a value object is one of 
the most difficult things to decide.

Regards
Jochen

-- 
"Every nit picked is a bug fixed"