objective c - NSManagedObjectContext: autoupdate or not? -

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i need understand nsmanagedobjectcontext update. have uisplitview uitableviewcontroller on rootview , uiviewcontroller on detail view. when tap in row data, load data labels , uitextview can update field:

- (void)textviewdidendediting:(uitextview *)textview { nsindexpath *indexpath = [self.tableview indexpathforselectedrow]; [[listofadventures objectatindex:indexpath.row] setadventuredescription:textview.text]; }

ok. works correctly, description updated. also, might wants delete row:

- (void)tableview:(uitableview *)tableview commiteditingstyle:(uitableviewcelleditingstyle)editingstyle forrowatindexpath:(nsindexpath *)indexpath {  if (editingstyle == uitableviewcelleditingstyledelete) {     nspredicate *predicate = [nspredicate predicatewithformat:@"playerplaysadventure.adventurename==%@",[[listofadventures objectatindex:indexpath.row] adventurename]];     nsarray *results = [[adventurefetcher sharedinstance] fetchmanagedobjectsforentity:@"player" withpredicate:predicate withdescriptor:@"playername"];      [moc deleteobject:[listofadventures objectatindex:indexpath.row]];     ( player *player in results ) {         [moc deleteobject:player];     }     [listofadventures removeobjectatindex:indexpath.row];     [tableview deleterowsatindexpaths:[nsarray arraywithobject:indexpath] withrowanimation:yes];     [self cleardetailviewcontent];     nserror *error = nil;     if ( ![moc save:&error] ) {         nslog( @"errore nella cancellazione del contesto!" );         abort();     } }    else if (editingstyle == uitableviewcelleditingstyleinsert) {     // create new instance of appropriate class, insert array, , add new row table view }    }

so here's problem: if comment rows saving of moc, adventure momentarily deleted. if quit app , reopen it, object still there. doesn't happen update of field. i'd know why , if should save moc in textviewdidfinishediting method. thank in advance.

it's difference between changing attribute of object , adding or removing entire object in object graph.

in first block, change attribute of existing object saves automatically unless run undo. because object exist in object graph , no other objects have altered make change.

in second block, removing entire object , potentially altering object graph changing relationships between objects. change not committed until implicit save because potentially can trigger cascade of changes throughout large number of objects.


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