HP 3000 Manuals

ALLBASE/SQL Performance Guidelines

Using TID Scans 

When the tuple ID (TID) is known, you can access a particular row without
using an index.  Use the TID() function in a SELECT statement to provide
TIDs for later use in manipulating an individual row.

The TID scan provides the fastest possible data access when you need to
access a single row in a singleton SELECT, or in a non-cursor UPDATE or
DELETE statement.  Cursor operations do not benefit from the use of the
TID() function.

MPE/iX 5.0 Documentation