The matching criteria to apply to records.
- iOS 8.0–10.0Deprecated
- macOS 10.10–10.12Deprecated
- UIKit for Mac 13.0–13.0Deprecated
- tvOS 9.0–10.0Deprecated
A query-based subscription uses its search predicate to identify potential matches for records. It combines the predicate information with the value in the
subscription property to determine the conditions under which to send a push notification to the app.
The search predicate defines the records that the subscription object monitors for changes. The value in this property is used only if the
subscription property is set to
CKSubscription; otherwise, it is ignored.
A query-based subscription can be used to observe multiple records or a single record. An example of subscribing to the changes of a single record is shown below: