The LOGON statement causes Teradata ARC to log on only two control sessions for the user.
When Teradata ARC encounters ARCHIVE, RESTORE, or COPY, it automatically logs on any additional data sessions specified in the SESSIONS runtime parameter. ARCHIVE, RESTORE, and COPY are the only statements that need these sessions.
- Identifying the user to the Teradata Database
- Specifying the account to charge for system resources
When LOGON is accepted, this message is displayed:
2 SESSIONS LOGGED ON
If the user who is specified by userid is logged onto the Teradata Database through a program other than Teradata ARC, Teradata ARC terminates as soon as it encounters BUILD, COPY, RESTORE, ROLLBACK, or ROLLFORWARD. To determine whether a user is logged onto the Teradata Database, Teradata ARC performs a SELECT on database DBC.sessionInfo. Therefore, the user attempting to log on must have SELECT privileges on DBC.sessionInfo.
If a LOGON statement has already been run by Teradata ARC, Teradata ARC logs off all Teradata Database sessions from the previous logon.
The implementation of the SSO feature provides the ability to log onto a workstation once and then access the Teradata Database without having to provide a user name and password. SSO saves the time required to enter these fields, which are now optional. Additionally, certain authentication mechanisms (e.g., Kerberos, NTLM) do not send passwords across the network to further heighten security. SSO requires support of both the database and the client software.