Hi ! I'm fairly new at using coreData on and I'd like to have some clarifications on managedObjects and contexts usage. I have a model where a top entity has a couple to-many relationships, which each have to-many relationships to other entities. something like this :
A to-many -> B to-many -> C B to-many -> D C to-many -> E (I skipped the other attributes in the entities) I have a set of As, that I fetch when my app loads, and I dig into As through a UITableView. I show a list of As, and when the user taps an A, I show a detail view of its contents. The user can then access the table of Bs and Cs. And add Ds and Es... What I'd like to know is what I should do when I show the list of Bs for example. Should I do a new fetch (with a different fetchRequest) on the Bs, and have this as a new context ? I'm not sure how do NSIndexPath work with my setup ? My feeling is that if I do the new fetchRequest on the Bs, then a path of 0.x will give me the "array" indexes of my Bs. But if I stay with the original context, how can it know of the two separate inner sets (B,C) ? On the other hand, the same data has already been loaded when I loaded the As. (well, they may have only been faulted). Is it usual to "re-load" some parts of the tree ? Also, when adding Ds should I pass the managed B object to my BviewController and do [Binstance addDObject: newD]; or have B as the base of the new context and do [NSEntityDescription insertNewObjectForEntityForName:@"D" ...] or if I didn't do any new fetchRequest (staying with the As), will [Binstance addDObject: newD]; still do the relevant work in the hierarchy ? and last question (see I'm still a bit confused about the whole thing :)) if I keep the context I got when loading the original As, and I do a [context save:] of new Ds, will it be as efficient as if I was to do the same thing with a context created with Bs as a fetchRequest ? thanks for any enlightenments. I get the feeling that one can use a coredata hierarchy almost as directly as if it was a plain object hierarchy, but I'd like to make sure I'm not missing something along the way ! thanks ! _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
