Hi Bruce,
I don't have the time to continue exploring this with you today, but to answer your question, I have used detail data sources when passing an object from one component to the next. For example, you can select an object from a displayGroup on one page and set it as the master object of a master/detail displayGroup on the following page. If you don't have the detail data source, you don't see the binding for masterObject in WOBuilder. In truth, I expect that following the paths to the attribute you want to display as I showed in the example yesterday makes the Master/Detail configuration unnecessary.
Having said that, my guess is that the tutorial would have worked fine with a normal to-many relationship. The example in the tutorial contains a model that is more complicated than I usually use because of the accessible attribute "roleName" in the join entity MovieRole (normally I would just have the two foreign keys in the join table and leave it as an artifact in the database). Having MovieRole as an object arbitrarily seems to change the Entity type of your WODisplayGroup as you select different Master and Detail entities. I haven't seen this behaviour before and it doesn't seem to be logical.
As an experiment, you could try and make a simple EOModel with Teacher and Class entities and see if the tutorial example works for that.
Teacher {id, firstName, lastName}
Class {id, subject, fk_teacher_id}
to-many Teacher to Classes
You could try dragging the classes relationship to the WOComponent in WOBuilder (which should create a classesDisplayGroup) and go from there...
David
On 16 Feb 2007, at 6:39 AM, Bruce Smith wrote:
what exactly is "Has detail data source" for?