16.20 - Teradata Unity Support for External Procedures - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ SQL Data Definition Language Detailed Topics

Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Release Date
March 2019
Content Type
Programming Reference
Publication ID
B035-1184-162K
Language
English (United States)

Teradata Unity sends request-specific context information as part of a request that calls an external procedure to enable Teradata Database to change the result of the executed procedure indirectly by substituting a value predefined by Teradata Unity for a non-deterministic result. Teradata Database makes this context information available to an external procedure when it is called from the default connection for the session.

However, external procedures can generate and use their own arbitrary non-deterministic values that Teradata Database has no knowledge of. Therefore, Teradata Database cannot guarantee that an external procedure call produces a consistent result.

An external procedure can create a separate connection to another database, or to the same database by means of logging onto another session. In this case, the Teradata Unity-provided context information is not available for any SQL submitted using this type of connection.