predicate
The matching criteria to apply to records.
Declaration
@NSCopying var predicate: NSPredicate { get }Discussion
A query-based subscription uses its search predicate to identify potential matches for records. It combines the predicate information with the value in the querySubscriptionOptions property to determine when to send a push notification to the app.
The search predicate defines the records that the subscription object monitors for changes. The system only uses the property’s value when the subscriptionType property is CKSubscription.SubscriptionType.query. Otherwise, the system ignores it.