A database request is sent to the database by a CLIv2 application using an established database session. The response to a request is created by the database. Each request is identified to the application and to the database by a request number. A request number is assigned by TDP and is unique for a given session. It is known to the database.
A request either succeeds or fails. If any part of the request fails, any effects are backed out—the database remains unchanged.
The response is normally received sequentially by the application, but direct access to selected portions of the response is also supported. While up to sixteen completed responses can exist for a session at any one time, only one request can be active for a session at any time.