Microsoft.Data.SqlClient.SqlNotificationType
Describes the different notification types that can be received by an OnChangeEventHandler event handler through the SqlNotificationEventArgs parameter.
Change = 0
Data on the server being monitored changed. Use the SqlNotificationInfo item to determine the details of the change.
Subscribe = 1
There was a failure to create a notification subscription. Use the SqlNotificationEventArgs object's SqlNotificationInfo item to determine the cause of the failure.
Unknown = -1
Used when the type option sent by the server was not recognized by the client.