Doesn't work for sorting in NSFetchedresultsController On Aug 15, 2013, at 16:34 , Sandor Szatmari <admin.szatmari....@gmail.com> wrote:
> Can you make it a derived property? If each Managed object has a reference > to the AppDelegate they can just return the comparison of their > NSManagedObjectID to the one stored as the user default. > > Sandor Szatmari > > On Aug 15, 2013, at 1:07, Rick Mann <rm...@latencyzero.com> wrote: > >> >> On Aug 14, 2013, at 21:14 , Jerry Krinock <je...@ieee.org> wrote: >> >>> >>> On 2013 Aug 14, at 20:46, Keary Suska <cocoa-...@esoteritech.com> wrote: >>> >>>> A cleaner approach, IMHO, is to have a holder entity whose sole attribute >>>> is a to-one relationship to your other entity. Think of it as a singleton >>>> that always exist and maintains the particular managed object. >>> >>> Indeed Keary's idea is much better, and furthermore you may well already >>> such an existing "singleton" entity nearby in that data model, which would >>> be the logical place for this to-one relationship. Just add this >>> relationship to that existing "singleton" entity. >> >> On Aug 14, 2013, at 20:46 , Keary Suska <cocoa-...@esoteritech.com> wrote: >> >>> On Aug 14, 2013, at 6:28 PM, Rick Mann wrote: >>> >>>> I have a boolean property on an Entity for which only one should ever be >>>> true. Is it really bad to implement a custom setter that loads every other >>>> instance in the MOC that's true and sets them all to false? My code is >>>> actually good about always clearing the current one before setting the new >>>> one, but when I'm debugging, I will copy data over from another device, >>>> and it can't clear the old one in this case. >>> >>> I am not sure if it bad, but it sure smells funny ;-) Anyway, the issue may >>> be more of the data approach. It is likely that the boolean attribute >>> shouldn't belong to the entity at all--i.e. that the attribute is really >>> for needed by some other object or process and is not a function of the >>> entity. A cleaner approach, IMHO, is to have a holder entity whose sole >>> attribute is a to-one relationship to your other entity. Think of it as a >>> singleton that always exist and maintains the particular managed object. It >>> also requires no code at all to maintain uniqueness--simply assign the >>> relationship. >> >> Well, I used to store the active instance as a property of my app >> (AppDelegate). I'd store the NSManagedObjectID as a user default. >> >> Unfortunately, I need to be able to sort on the boolean property, and on an >> NSFetchedResultsController at that, which won't sort on transient properties. >> >> Moreover, it seems extraordinarily clumsy to have another entity >> representing the app, and to only have a singleton of that. >> >> -- >> Rick >> >> >> >> >> _______________________________________________ >> >> Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) >> >> 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: >> https://lists.apple.com/mailman/options/cocoa-dev/admin.szatmari.net%40gmail.com >> >> This email sent to admin.szatmari....@gmail.com -- Rick _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
