On Jul 19, 2014, at 12:37 , Jerry Krinock <je...@ieee.org> wrote: > > On 2014 Jul 18, at 15:54, Rick Mann <rm...@latencyzero.com> wrote: > >> Is it wrong to create relationships in >> -createDestinationInstancesForSourceInstance:…? > > Yes, it is wrong, according “Three Stage Migration” of the Core Data Model > Versioning and Data Migration Programming Guide… > > https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CoreDataVersioning/Articles/vmMigrationProcess.html#//apple_ref/doc/uid/TP40004399-CH6-SW8
Huh. Sure enough, it says, "In this stage, only attributes (not relationships) are set in the destination objects." However, I had decided that there was no good reason not to set a relationship between two new destination objects if they were both created in one -create… call, and proceeded to do it anyway. Worked fine. Then I discovered that you don't need to do that, if you leverage all the automatic capabilities afforded by automatic migration. Simply by calling -[super create…], you can get the bulk of the work done by specifying expressions in the Mapping Model editor, and it's got a much more compact (if somewhat unwieldy) way of specifying the new relationships. Once I realized that, my actual code got a lot smaller and tidier. -- Rick Mann rm...@latencyzero.com _______________________________________________ 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
