16.20 - AS DEFAULT Option - Teradata Vantage NewSQL Engine

Teradata Vantage™ SQL Data Control Language

prodname
Teradata Database
Teradata Vantage NewSQL Engine
vrm_release
16.20
created_date
March 2019
category
Programming Reference
featnum
B035-1149-162K

A request that includes the AS DEFAULT option has no effect on the logon access granted to or revoked from specific user names.

The following rules apply to the AS DEFAULT option:

Statement Privileges Assumed
REVOKE LOGON The user cannot access the applicable client even if that client has an assigned default of GRANT.
GRANT LOGON The user can always access the applicable client even if that client has an assigned default of REVOKE.

Note in the following examples that these two requests do not have the same semantics:

REVOKE LOGON ON ALL AS DEFAULT;

REVOKE LOGON ON ALL FROM "DEFAULT";

The first request revokes logon privileges on any source through which a logon is attempted, including the Teradata Database console, without residual conditions. Note that the string AS DEFAULT in this request is a keyword phrase and does not identify a user.

In the second request, Teradata Database treats “DEFAULT” as a string literal that identifies a user, not as a keyword, and the request revokes logon privileges on all logon sources for the user named DEFAULT. Because DEFAULT is a dummy user name and cannot logon to Teradata Database, the second request, though syntactically valid, essentially has no effect.