I see the term object domain used a lot these days but I'm hardpressed to understand what it actually is.
Can someone please tell me what an object domain is and perhaps give an example?
many thanks.
Bruce Prior
On 12-07-06 11:24 AM, Bruce Prior wrote:
I see the term object domain used a lot these days but I'm hardpressed to understand what it actually is.
Can someone please tell me what an object domain is and perhaps give an example?
many thanks.
Bruce Prior
Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
I'll take a shot and somebody can correct me. The domain is related to your data, your database, how you modeled the problem into pieces of data. So the object domain would be the objects related to holding or delivering data from you persistence/database.
In the MVC, model/view/controller, pattern the model is the data/database. The view presents it to an input device i.e. screen or web page. The controllers work between the two.
The object domain would be the model objects. A SQL database, say.
That's my take.
Chris
If you were modeling a soda can vending machine, you might have classes to model the domain including Can, Money, and Dispenser. Example from: http://www.amazon.com/Object-Oriented-Programming-Yourdon-Press-Computing/dp...
I think a lot of people think of the domain as the database, but I've always thought of the database as how you store your domain model, not the domain model itself.
The object store is concerned with state. Domain objects have state and behavior.
See Fowler: http://martinfowler.com/eaaCatalog/domainModel.html
Note that many systems written in object-oriented languages don't have domain models by this definition. Compare with, say, Table Model from the same book.
--David Mitchell (@davidmitchell) www.withaguide.com
On Fri, Jul 6, 2012 at 10:30 AM, Chris Cunnington < smalltalktelevision@gmail.com> wrote:
On 12-07-06 11:24 AM, Bruce Prior wrote:
I see the term object domain used a lot these days but I'm hardpressed to understand what it actually is.
Can someone please tell me what an object domain is and perhaps give an example?
many thanks.
Bruce Prior
Beginners mailing listBeginners@lists.squeakfoundation.orghttp://lists.squeakfoundation.org/mailman/listinfo/beginners
I'll take a shot and somebody can correct me. The domain is related to your data, your database, how you modeled the problem into pieces of data. So the object domain would be the objects related to holding or delivering data from you persistence/database.
In the MVC, model/view/controller, pattern the model is the data/database. The view presents it to an input device i.e. screen or web page. The controllers work between the two.
The object domain would be the model objects. A SQL database, say.
That's my take.
Chris
Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
I agree with David's statement below, generally. It's worth noting that in Smalltalk, our object memory + virtual machine together serve as a kind of non-relational database which preserves both state and behavior, but one doesn't generally have to think about it and that's beautiful:)
Even in SQL one has triggers and stored procedures, so perhaps the distinction is pervasively arbitrary. Someday we may have fast non-volatile RAM and no separate long term storage, at which point databases and persistence as we popularly think about them may even disappear entirely.
One of Smalltalk's offspring, the Self language, uses message sends (as far as the programmer is concerned) to access state, and thus does away with assignment in the usual/low-level sense. This is fun to think about (for me anyway!)
Someone please correct me if I'm wrong here, but I think of "object domain" and "object model" (where the word model is distinct from and more general than the Model in MVC) as being interchangeable.
I think of an object domain as just the set of objects which implements a feature or solves a problem. I suppose I may have my terminology mixed up though, so sound off if I'm wrong here folks:)
--Casey Ransberger
On Jul 6, 2012, at 2:42 PM, David Mitchell david.mitchell@gmail.com wrote:
I think a lot of people think of the domain as the database, but I've always thought of the database as how you store your domain model, not the domain model itself.
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