objective c - Core Data match a to many relationship to a list -
related this question, occured new 1 :
say have these attributes : [red, green, blue]
how can fetch objects or attributes in list, but in list only ?
* object_1 (red, green, blue) * object_2 (red, green) * object_3 (red)
this means not fetch object_4 (red, green, blue, yellow)
because has yellow
not in list
you can make compound predicate can add 3 predicates :
nspredicate *predone = [nspredicate predicatewithformat:@"color == %@",@"red"]; nspredicate *predtwo = [nspredicate predicatewithformat:@"color == %@",@"blue"]; nspredicate *predthree = [nspredicate predicatewithformat:@"color == %@",@"green"]; nsarray *allpredicates = [[nsarray alloc] initwithobjects:predone,predtwo,predthree, nil]; nspredicate finalpredicate = [nscompoundpredicate andpredicatewithsubpredicates:allpredicates];
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