dummy question: what is domain object?

[Lipman Li]

Hi,
what is the definition for domain class?
does it mean domain object must be persistent?
could we call the intermediate working object as domain object?

[Sanjay Raghavan]

Hi,
Don't know if what you want is the Domain Class Diagram...Let me use an example from Petstore...
Consider the following EJBs - Account, Order and Inventory.
The Account domain is actually represented by 2 classes - AccountEJB and a dependent object class called ContactInfo. Here the Account Domain can be said to be made up of the two classes.
Similarly Order and LineItems makes up Order domain and Inventory and Item makes up the Inventory Domain.
HTH.

[Lipman Li]

So, all the domain object must be stored into database, if it is not, it could not be called as domain object.

[Lipman Li]

excuse me, my english is poor.
let me make the question clear, by one example.
in an e-commerce web site, customer make payment by creditcard, and the web site will send the payment request (include credit card number, amount due) to credit card Authority to verify.
now the question is: is the payment request object a domain object?
we definitely are not going to store payment request into database.

[SC Johnson]

A domain object does not imply a persistent class. Domain objects are *analysis* objects. They exist solely to help the analyst undertand the relationship between concepts in the system.
Many domain objects end up as persistent classes, but don't assume you are creating an ER diagram.
Once again, the domain class diagram is a communication tool between the analyst, customer, and eventually the designer.

[Lipman Li]

Johnson,
yeah, agree with you. I'm trying not to think database & table, the situation is getting better.
regards

[Alexander Yanuar Koentjara]

Originally posted by Lipman Li:
Hi,
what is the definition for domain class?
does it mean domain object must be persistent?
could we call the intermediate working object as domain object?

http://www.martinfowler.com explain that very well...