Makes an asynchronous request for notification of a database event. All events, including the release of all read locks, are reported.

When a database event occurs, the request completes and the TRequestStatus objectcontains one of the enumerators defined by the TEvent enumeration member.

Alternatively, if an outstanding request is cancelled by a call to the Cancel() member function of this class, then the request completes with KErrCancel.

Only one notification request can be outstanding on this notifier at any one time.

Note that if further database events occur while a client is handling a request completion, the notifier records the most significant database event and this is signalled as soon as the client issues the next NotifyUnlock() or NotifyChange() request.

Opens a DBMS change notifier on a database.

Note that a notifier cannot be opened on a client side database.

Defines the events which may be reported by a DBMS change notifier through this RDbNotifier object.

Each enumerator corresponds to a distinct event type.

The changes are reported through a TRequestStatus object when an outstanding notification request completes.

Notes

If further database events occur while a client is handling the completion of a previous event, the notifier remembers the most significant event. The order of importance is:

ERecover > ERollback > ECommit

where the symbol > means "is more important than"