Requests are sent by an application to the database to initiate an action. Responses are sent by the database to the application to reflect the results of that action. Both requests and responses are associated with an established session. One or more Teradata SQL statements that are submitted to the database at the same time are called a Teradata SQL request.
Having several statements carried in the same request saves message transfer time. This is important to CPU- and I/O-bound programs or sites because a two-statement multi-statement request uses half the local (not the database) CPU time of two single statement requests.
Most requests contain the data needed for their completion, but a few require additional data. For example, requests that either insert a large database field, such as a picture, or define a program to run within the database, first prompt CLI to supply the data or program. The application then continues the request by providing the data or program.