# 6.6. ODPI-C Enumeration dpiEventType

This enumeration identifies the types of events that can take place. The event type is part of the messages that are sent to subscriptions.

Value | Description
--- | ---
DPI_EVENT_AQ | Indicates that a queue has messages available to dequeue.
DPI_EVENT_DEREG | Indicates that a subscription is no longer registered with the database and will no longer generate events.
DPI_EVENT_NONE | Indicates that no event has taken place.
DPI_EVENT_OBJCHANGE | Indicates that an object change has taken place.
DPI_EVENT_QUERYCHANGE | Indicates that a query change has taken place.
DPI_EVENT_SHUTDOWN | Indicates that a database is being shut down.
DPI_EVENT_SHUTDOWN_ANY | Indicates that an instance of Oracle Real Application Clusters (RAC) is being shut down.
DPI_EVENT_STARTUP | Indicates that a database is being started up.