Hi Adam,
Adam Jensen wrote:
See why it's helpful to be able to construct the Travel_Trip object
from the row? It saves Travel_Trip from having to reload an
already-loaded row from the database. It does so, however, at the
expense of Travel_Agent being aware of the fact that Travel_Trip is
backed by a database table.
Comments? Is there a way to keep from having to reload the row
without exposing Travel_Trip's database dependency?
The more you want your domain objects to be ignorant of the database
storage, the more you're going to need a separating layer, such as a
Data Mapper [1], to isolate the dependencies. It's a classic trade-off:
the simplicity of directly modeling the table structure conflicts with
the flexibility and expressiveness of "pure" objects. You just have to
pick a comfortable point on that continuum for your application. :)
[1]
http://martinfowler.com/eaaCatalog/dataMapper.html
Regards,
Bryce Lohr
