A collection of either property descriptions or string property names that specify which properties should be returned by the fetch.
- iOS 3.0+
- macOS 10.6+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
- Core Data
Property descriptions can either be instances of
NSString. The property descriptions may represent attributes, to-one relationships, or expressions. The name of an attribute or relationship description must match the name of a description on the fetch request’s entity.
You must set the entity for the fetch request before setting this value; otherwise,
NSFetch throws an
This property can be set with
NSManaged and thereby implement a partial faulting (whereby only some of the properties are populated) of the returned objects, as well as the
NSDictionary to define what properties are included in the resulting