Using Identity Columns
The most frequent use of identity columns is as surrogate keys. An identity column is an optional column attribute. When you associate an identity column attribute with a column, Teradata Database generates a table‑level unique number for the column for every inserted row.
Identity column values are returned as part of the response, if an AGKR (Auto Generated Key Retrieval) option flag in the request-level Options parcel is set, when an INSERT or INSERT … SELECT request is executed.